Impact of Infection Prevention Programs on Catheter-Associated Urinary Tract Infections Analyzed in Multicenter Study.

BACKGROUND: Catheter-associated urinary tract infections (CAUTIs) account for a large proportion of healthcare-associated infections and have a significant impact on morbidity, length of hospital stay, and mortality. Adherence to the recommended infection prevention practices can effectively reduce the incidence of CAUTIs. This study aimed to assess the characteristics of CAUTIs and the efficacy of prevention programs across hospitals of various sizes. METHODS: Intervention programs, including training, surveillance, and monitoring, were implemented. Data on the microorganisms responsible for CAUTIs, urinary catheter utilization ratio, rate of CAUTIs per 1,000 device days, and factors associated with the use of indwelling catheters were collected from 2017 to 2019. The incidence of CAUTIs and associated data were compared between university hospitals and small- and medium-sized hospitals. RESULTS: Thirty-two hospitals participated in the study, including 21 university hospitals and 11 small- and medium-sized hospitals. The microorganisms responsible for CAUTIs and their resistance rates did not differ between the two groups. In the first quarter of 2018, the incidence rate was 2.05 infections/1,000 device-days in university hospitals and 1.44 infections/1,000 device-days in small- and medium-sized hospitals. After implementing interventions, the rate gradually decreased in the first quarter of 2019, with 1.18 infections/1,000 device-days in university hospitals and 0.79 infections/1,000 device-days in small- and medium-sized hospitals. However, by the end of the study, the infection rate increased to 1.74 infections/1,000 device-days in university hospitals and 1.80 infections/1,000 device-days in small- and medium-sized hospitals. CONCLUSION: We implemented interventions to prevent CAUTIs and evaluated their outcomes. The incidence of these infections decreased in the initial phases of the intervention when adequate support and personnel were present. The rate of these infections may be reduced by implementing active interventions such as consistent monitoring and adherence to guidelines for preventing infections.

Incidence and risk factors of COVID-19 in a tertiary hospital and the effectiveness of booster vaccination among health care workers: A retrospective cohort study, January 2020 to June 2022.

BACKGROUND: Health care workers (HCWs) face a higher risk of infection and may transmit pathogens to patients during a pandemic. This study aims to evaluate infection-control measures by analyzing the incidence and risk factors of COVID-19 and estimating vaccine effectiveness (VE) at a tertiary hospital in Seoul, Republic of Korea. METHODS: This study included 2,516 HCWs from January 1, 2020, to June 30, 2022. Data were analyzed to determine the incidence density and cumulative incidence; the results were compared by the age- and gender-specific standardized incidence ratios (SIR). VE was estimated with multivariate Cox proportional-hazard models as 1-adjusted hazard ratio × 100%. RESULTS: SIR indicated a lower COVID-19 risk in the hospital population than in the general Korean population (SIR, 0.81; 95% confidence interval [CI]: 0.76-0.87). Multivariate Cox analysis indicated that, compared to doctors, nonmedical service supporters and other HCWs (excluding doctors and nurses) were high-risk groups (adjusted hazard ratio [95% CI], 1.72 [1.04-2.83] and 1.76 [1.20-2.58], respectively). Compared to the outpatient unit, the emergency department was a high-risk department (1.70 [1.16-2.50]). The VE of the booster dose was 55.47%, compared to no or incomplete vaccination (95% CI: 22.63-74.37). CONCLUSIONS: Besides encouraging HCWs vaccination, effective infection-control measures should target high-risk groups and departments.

External and internal validation of healthcare-associated infection data collected by the Korean National healthcare-associated Infections Surveillance System (KONIS).

BACKGROUND: This study analyzed the validity of healthcare-associated infection (HAI) data of the Korean National healthcare-associated Infections Surveillance System. METHODS: The validation process consisted of external (EV) and internal (IV) validation phases. Of the 193 hospitals that participated from July 2016 through June 2017, EV was performed for 10 hospitals that were selected based on the HAI rate percentile. The EV team reviewed 295 medical records for 60 HAIs and 235 non-HAI control patients. IV was performed for both the 10 EV hospitals and 11 other participating hospitals that did not report any HAIs. RESULTS: In the EV, the diagnosis of urinary tract infections had a sensitivity of 72.0% and a specificity of 99.3%. The respective sensitivities of bloodstream infection and pneumonia were 63.2% and 70.6%; the respective specificities were 98.8% and 99.6%. The agreement (ĸ) between the EV and IV for 10 hospitals was 0.754 for urinary tract infections and 0.674 for bloodstream infections (P < .001, respectively). Additionally, IV found additional cases among 11 zero-report hospitals. DISCUSSION: This study demonstrates the need for ongoing validation and continuous training to maintain the accuracy of nationwide surveillance data. CONCLUSIONS: IV should be considered a validation method to supplement EV.

Relative Effectiveness of COVID-19 Vaccination in Healthcare Workers: 3-Dose Versus 2-Dose Vaccination.

The omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to have high infectivity and is more likely to evade vaccine immunity. However, booster vaccination is expected to strengthen cross-reactive immunity, thereby increasing the vaccine effectiveness (VE). This study aimed to evaluate the relative VE of the 3-dose (booster) vaccination compared with the 2-dose primary series vaccination in healthcare workers during omicron variant-dominant periods. During the omicron-dominant period from February 1, 2022 to February 28, 2022, a 1:1 matched case-control study was conducted. Healthcare workers with positive SARS-CoV-2 test results were classified as positive cases, whereas those with negative results served as controls. Compared with the 2-dose primary series vaccination, booster vaccination with mRNA vaccine showed moderate VE (53.1%). However, in multivariate analysis including the time elapsed after vaccination, the significant VE disappeared, reflecting the impact of recent vaccination rather than the third dose itself.

Early Safety Monitoring of COVID-19 Vaccines in Healthcare Workers.

Hospital-based surveillance for adverse events was conducted on healthcare workers after they received the first dose of coronavirus disease 2019 (COVID-19) vaccine. Among the two new platform vaccines (messenger RNA- and adenoviral vector-based vaccines), the rates of systemic adverse events were significantly higher among adenovirus-vectored vaccine recipients. Fatigue (87.6% vs. 53.8%), myalgia (80.8% vs. 50.0%), headache (72.0% vs. 28.8%), and fever (≥ 38.0°C, 38.7% vs. 0%) were the most common adverse events among adenovirus-vectored vaccine recipients, but most symptoms resolved within 2 days. Both types of COVID-19 vaccines were generally safe, and serious adverse events rarely occurred.

Positivity of Carbapenemase-producing Enterobacteriaceae in Patients Following Exposure within Long-term Care Facilities in Seoul, Korea.

BACKGROUND: Carbapenemase-producing Enterobacteriaceae (CPE) are emerging as a worldwide threat. Long-term care facilities (LTCFs) are considered a reservoir for CPE and play a central role in transmission to acute care hospitals. We investigated the CPE positivity in patients exposed to CPE in LTCFs. Furthermore, we analyzed the CPE positivity rates in the environment exposed to CPE. METHODS: We collected rectal swab specimens from patients residing in LTCFs who were exposed to CPE. Environmental sampling was performed by infection control practitioners from sites classified as patient private space, common space in the patient room, common space other than patient rooms, and nursing station. Each sample was cultured on a Chrom Klebsiella pneumoniae carbapenemase (KPC) agar for CPE screening. The positive isolates were subjected to a polymerase chain reaction to identify the presence of blaKPC, blaVIM, blaIMP, blaOXA-48, and blaNDM and determine CPE genotype. RESULTS: From 65 index cases, a total of 24 hospitals and 481 patients were enrolled; 414 patients who had resided in the same patient room as a patient with confirmed CPE and 67 patients who were newly admitted to that patient room. A total of 117 (24.3%) patients were positive for CPE among which 93 (22.5%, 93/414) were already admitted patients and 24 (35.8%, 24/67) were newly admitted patients. A total of 163 CPEs were detected and K. pneumoniae (n = 104, 63.8%) was the most common bacteria followed by Escherichia coli (n = 43, 26.4%) and Citrobacter koseri (n = 11, 6.7%). Environmental sampling was performed in 24 hospitals and 604 sites. A total of 12 sites (2.0%) were positive for CPE and sink in the nursing station (n = 6, 4.2%) was the most contaminated space. CONCLUSION: CPE colonization rates in patients exposed to CPE in LTCFs were higher than those found in acute care hospitals. Proper infection control measures for detecting and reducing CPE colonization in patients residing in LTCFs are required. Newly admitted patients could also be carriers; therefore, infection control for newly admitted patients also needs to be thorough.

Impact of national policy on hand hygiene promotion activities in hospitals in Korea.

BACKGROUND: After the Middle East respiratory syndrome coronavirus outbreak in Korea in 2015, the Government established a strategy for infection prevention to encourage infection control activities in hospitals. The new policy was announced in December 2015 and implemented in September 2016. The aim of this study is to evaluate how infection control activities improved within Korean hospitals after the change in government policy. METHODS: Three cross-sectional surveys using the WHO Hand Hygiene Self-Assessment Framework (HHSAF) were conducted in 2013, 2015, and 2017. Using a multivariable linear regression model, we analyzed the change in total HHSAF score according to survey year. RESULTS: A total of 32 hospitals participated in the survey in 2013, 52 in 2015, and 101 in 2017. The number of inpatient beds per infection control professionals decreased from 324 in 2013 to 303 in 2015 and 179 in 2017. Most hospitals were at intermediate or advanced levels of progress (90.6% in 2013, 86.6% in 2015, and 94.1% in 2017). In the multivariable linear regression model, total HHSAF score was significantly associated with hospital teaching status (ß coefficient of major teaching hospital, 52.6; 95% confidence interval [CI], 8.9 to 96.4; P = 0.018), beds size (ß coefficient of 100 beds increase, 5.1; 95% CI, 0.3 to 9.8; P = 0.038), and survey time (ß coefficient of 2017 survey, 45.1; 95% CI, 19.3 to 70.9; P = 0.001). CONCLUSIONS: After the new national policy was implemented, the number of infection control professionals increased, and hand hygiene promotion activities were strengthened across Korean hospitals.

A Nationwide Survey on the Hospital Vaccination Policies in Korea.

BACKGROUND: Healthcare personnel (HCP) are at risk of being exposed to or transmitting infections in hospitals, and vaccination against vaccine-preventable diseases (VPDs) is a well-known preventive strategy. Vaccination against influenza, hepatitis B virus, measles-mumps-rubella, varicella, and pertussis is recommended for HCP. However, there is no information on the current status of hospitals' vaccination policies for HCP in Korea. METHODS: We conducted a nationwide survey on hospital vaccination policies and barriers to implementing recommended vaccination programs in 2018. The online survey questionnaire was distributed to 652 hospitals, and 200 of them responded. RESULTS: Of the 200 surveyed hospitals, 151 (75.5%) conducted a pre-employment screening program for at least one VPD, and 196 (98%) had vaccination programs that included at least one vaccine. Influenza vaccine was most commonly included in their programs (97.5%, n = 195), followed by hepatitis B vaccines (69%, n = 138). However, < 25% of the hospitals included other vaccines in their policies (measles-mumps-rubella, 24.5%; varicella, 18.5%; pertussis, 11%). Only 13 hospitals (6.5%) included the five recommended vaccines for HCP in their policies. Influenza vaccination coverage had a mean of 89.9% and was significantly higher in hospitals fully funding the vaccination cost (91.8% vs. 80.4%, P < 0.001). Among hospitals funding influenza vaccines, the coverage was lower in hospitals with ≥ 700 beds (-6.5%, P = 0.003). Hospitals' financial burden was the most important barrier to implementing vaccination polices as recommended (78.6%, 121/154), followed by lack of awareness (21%) or campaign (21%) and lack of leadership (17%). CONCLUSION: Despite the recommendations on vaccination for HCP, the vaccination policies for HCP differ in hospitals and appear to be insufficient to protect HCP and prevent nosocomial transmission. Strong leadership of each hospital to protect HCP and financial support from the government are required to implement appropriate vaccination policies in hospitals.

Trends in the Epidemiology of Candidemia in Intensive Care Units From 2006 to 2017: Results From the Korean National Healthcare-Associated Infections Surveillance System.

Candidemia is an important healthcare-associated infection (HAI) in intensive care units (ICUs). However, limited research has been conducted on candidemia in the Republic of Korea. We aimed to analyze the secular trends in the incidence and distribution of candidemia in ICUs over 12-years using data from the Korean National Healthcare-Associated Infections Surveillance System (KONIS). KONIS was established in 2006 and has performed prospective surveillance of HAIs including bloodstream infections (BSIs) in ICUs. We evaluated the trends in the distribution of causative pathogens and the incidence of candidemia. From 2006 to 2017, 2,248 candidemia cases occurred in 9,184,264 patient-days (PDs). The pooled mean incidence rates of candidemia significantly decreased from 3.05 cases/10,000 PDs in 2006 to 2.5 cases/10,000 PDs in 2017 (P = 0.001). Nevertheless, the proportion of candidemia gradually increased from 15.2% in 2006 to 16.6% in 2017 (P = 0.001). The most frequent causative pathogen of BSIs from 2006 to 2012 was Staphylococcus aureus; however, Candida spp. emerged as the most frequent causative pathogen since 2013. C. albicans (39.9%) was the most common among Candida spp. causing BSIs, followed by Candida tropicalis (20.2%) and Candida parapsilosis (18.2%). The proportion of candidemia caused by C. glabrata significantly increased from 8.9% in 2006 to 17.9% in 2017 (P < 0.001). There was no significant change in the distribution of Candida spp. by year (P = 0.285). The most common source of BSIs was central lines associated BSI (92.5%). There was a significant increase in the proportion of candidemia by year in hospitals with organ transplant wards (from 18.9% in 2006 to 21.1% in 2017, P = 0.003), hospitals with <500 beds (from 2.7% in 2006 to 13.6% in 2017, P < 0.001), and surgical ICUs (from 16.2% in 2006 to 21.7% in 2017, P = 0.003). The proportion of candidemia has increased in Korea, especially in hospitals with <500 beds and surgical ICUs. Thus, appropriate infection control programs are needed.

Ten-year surveillance of central line-associated bloodstream infections in South Korea: Surveillance not enough, action needed.

BACKGROUND: Central line-associated bloodstream infections (CLABSIs) are preventable health care-associated infections that can lead to increased mortality. Therefore, we investigated trends in CLABSI rates, and the factors associated with changing trends over a 10-year period using the Korean National Healthcare-associated Infections Surveillance System (KONIS). METHODS: We investigated annual CLABSI rates from 2006 to 2015 in 190 KONIS-participating intensive care units (ICUs) from 107 participating hospitals. We collected data associated with hospital and ICU characteristics and analyzed trends using generalized autoregressive moving average models. RESULTS: The CLABSI pooled mean rate decreased from 3.40 in 2006 to 2.20 in 2015 (per 1,000 catheter-days). The trend analysis also showed a significant decreasing trend in CLABSI rates in unadjusted models (annual increase, -0.137; P < .001). After adjusting for hospital and ICU characteristics, significant decreasing trends were identified (annual increase, -0.109; P < .001). However, there were no significant changes in subgroups with non-university-affiliated hospitals, hospitals in metropolitan areas near Seoul, small hospitals (300-699 beds), or surgical ICUs. CONCLUSIONS: In South Korea, CLABSI rates have shown significant reductions in the past 10 years with participation in the KONIS. However, CLABSI rates may be reduced by encouraging more hospitals to participate in the KONIS and by improved policy support for hospitals lacking infection control resources.

Viral Shedding and Environmental Cleaning in Middle East Respiratory Syndrome Coronavirus Infection.

Viral shedding lasted 31 and 19 days from symptom onset in two patients with east respiratory syndrome coronavirus (MERS-CoV) pneumonia, respectively. Environmental real-time RT-PCR was weakly positive for bed guardrail and monitors. Even after cleaning the monitors with 70% alcohol-based disinfectant, RT-PCR was still weakly positive, and converted to negative only after wiping with diluted sodium chlorite. Further studies are required to clarify the appropriate methods to clean environments during and after treatment of patients with MERS-CoV infection.

Middle East Respiratory Syndrome Infection Control and Prevention Guideline for Healthcare Facilities.

Middle East Respiratory Syndrome (MERS) is an acute viral respiratory illness with high mortality caused by a new strain of betacoronavirus (MERS-CoV). Since the report of the first patient in Saudi Arabia in 2012, large-scale outbreaks through hospital-acquired infection and inter-hospital transmission have been reported. Most of the patients reported in South Korea were also infected in hospital settings. Therefore, to eliminate the spread of MERS-CoV, infection prevention and control measures should be implemented with rigor. The present guideline has been drafted on the basis of the experiences of infection control in the South Korean hospitals involved in the recent MERS outbreak and on domestic and international infection prevention and control guidelines. To ensure efficient MERS-CoV infection prevention and control, care should be taken to provide comprehensive infection control measures including contact control, hand hygiene, personal protective equipment, disinfection, and environmental cleaning.

Dose sparing strategy with intradermal influenza vaccination in patients with solid cancer.

Influenza vaccine is considered to reduce influenza-related morbidity and mortality in patients with underlying chronic medical conditions. Because of fear of vaccine shortage during an influenza pandemic, several antigen sparing strategies have been investigated. The immunogenicity of intradermal influenza vaccination with one half the antigenic contents was compared to that of conventional intramuscular vaccination in patients with solid cancer, and adverse events were assessed after vaccination. There was no significant difference between the injection routes in the hemagglutinin inhibition (HI) response and increase in the titer of A/H1N1, A/H3N2, and B 4-6 weeks after the vaccination; seroconversion factors increased by more than 2.5-fold. Seroresponse rates were more than 40% and seroprotection rates were above 70% against all three influenza strains irrespective of the vaccination routes. No serious events were observed, and local skin reactions were more frequent in the intradermal injection recipients than in the intramuscular recipients (32.7% vs. 9.1%). This study shows that intradermal injection of one half the dose of a commercial influenza vaccine elicits immune responses comparable to those elicited by a full dose of intramuscular vaccine among cancer patients, and it can be tolerated without serious adverse reactions.

Ethanol extract of Psoralea corylifolia L. and its main constituent, bakuchiol, reduce bone loss in ovariectomised Sprague-Dawley rats.

The aim of the present study was to investigate whether ethanol extracts of Psoralea corylifolia L. (PCE) and its active component protect against bone loss in ovariectomised rats. We screened oestrogenic activities of the main extract fractions using in vitro assays and identified bakuchiol as the most active oestrogenic component by HPLC and LC/MS, and then demonstrated that bakuchiol had strong binding affinity for oestrogen receptor (ER) alpha. Seventy female Sprague-Dawley rats were assigned to either a sham-operated group (n 10) or an ovariectomised group (n 60). The ovariectomised group was subdivided into six groups, each containing ten rats: vehicle group, two bakuchiol-treated groups (dose of 15 mg/kg per d or 30 mg/kg per d; ten rats for each group), two PCE-supplemented groups (0.25 % or 0.5 % extracts of diets; ten rats for each group) and a 17beta-oestradiol (E2)-treated group (20 microg/kg per d). We recorded weight and feed intake every week, and killed all animals after 6 weeks. Blood was collected, and the uterus, kidneys and livers were removed. Bakuchiol has a three-fold higher binding affinity for ERalpha than for ERbeta. Bakuchiol and PCE treatments had no uterotrophic activity even though they demonstrated oestrogenic activity in the in vitro assays. Bakuchiol and PCE treatments reduced postmenopausal bone loss by increasing alkaline phosphatase, Ca concentrations, serum E2 concentration and bone mineral density, and by decreasing the inorganic P level. The present study indicated that bakuchiol and PCE treatments could protect against bone loss.

Estrogenic activities of isoflavones and flavones and their structure-activity relationships.

In this study, we assessed the relationships between the structure and estrogenicity of flavonoid derivatives. We evaluated estrogenicity via yeast transactivation assays, E-screen assays, and ER binding assays. Genistein and coumestrol in the yeast transactivation assay and biochanin A, genistein, and equol in the E-screen assay, have been shown to have profound estrogenic activities. Flavonoids, with the exception of biochanin A and daidzein, exhibit more profound selectivity for ER beta than for ER alpha. We compared several flavonoids in terms of estrogenicity, as well as relatively small structural differences including the position of the phenol ring and hydroxy groups, the substitution of hydroxy groups or methoxy groups, the opening of the phenol ring; glycitein vs. 4',6,7-trihydroxyisoflavone, biochanin A vs. genistein, apigenin vs. genistein, 7,4'-dihydroxyflavone vs. isoliquiritigenin. A quantitative structure-activity relationship study design was utilized to develop model equations for the estrogenic activities of flavonoid derivatives. The prediction of estrogenicity with regard to ER alpha shows a positive correlation with MW and AlogP, and a negative correlation with Apol and Area (r2 = 0.89 and q2 = 0.83). The prediction of estrogenicity with regard to ER beta reveals a positive correlation with the AlogP and Hbond acceptors, and a negative correlation with RadOfGyration (r2 = 0.77 and q2 = 0.72).

Hypoglycemic effects of a phenolic acid fraction of rice bran and ferulic acid in C57BL/KsJ-db/db mice.

Rice bran contains many phenolic acids, the most abundant of which is the antioxidant, ferulic acid (FA). We evaluated the hypoglycemic effects of a phenolic acid fraction (the ethyl acetate fraction, EAE) of rice bran and of FA in C57BL/KsJ db/db mice. Type 2 diabetic mice were allocated to a control group, an EAE group, or an FA group. Animals were fed a modified AIN-76 diet, and EAE or FA was administered orally for 17 days. There was no significant difference in body weight gain between groups. Administration of EAE and FA significantly decreased blood glucose levels and increased plasma insulin levels. EAE or FA groups had significantly elevated hepatic glycogen synthesis and glucokinase activity compared with the control group. Plasma total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were significantly decreased by EAE and FA administration. These findings suggest that EAE and FA may be beneficial for treatment of type 2 diabetes because they regulate blood glucose levels by elevating glucokinase activity and production of glycogen in the liver.

Antidiabetes and antiobesity effect of cryptotanshinone via activation of AMP-activated protein kinase.

Metabolic disorders, including type 2 diabetes and obesity, represent major health risks in industrialized countries. AMP-activated protein kinase (AMPK) has become the focus of a great deal of attention as a novel therapeutic target for the treatment of metabolic syndromes, because AMPK has been demonstrated to mediate, at least in part, the effects of a number of physiological and pharmacological factors that exert beneficial effects on these disorders. Thus, the identification of a compound that activates the AMPK pathway would contribute significantly to the treatment and management of such syndromes. In service of this goal, we have screened a variety of naturally occurring compounds and have identified one compound, cryptotanshinone, as a novel AMPK pathway activator. Cryptotanshinone was originally isolated from the dried roots of Salvia militorrhiza, an herb that is used extensively in Asian medicine and that is known to exert beneficial effects on the circulatory system. For the first time, in the present study, we have described the potent antidiabetic and antiobesity effects of cryptotanshinone, both in vitro and in vivo. Our findings suggest that the activation of the AMPK pathway might contribute to the development of novel therapeutic approaches for the treatment of metabolic disorders such as type 2 diabetes and obesity.

Effect of a hospital campaign for influenza vaccination of healthcare workers.

OBJECTIVE: To identify the factors that inhibit or motivate influenza vaccination among healthcare workers (HCWs). METHODS: In March 2000, we prepared 34-item questionnaire for both vaccine recipients and nonrecipients regarding demographic characteristics, factors motivating and inhibiting vaccination, and knowledge and attitudes about influenza vaccination. On the basis of the results of our survey, an aggressive hospital vaccination campaign was undertaken. In April 2004, after the 4-year campaign, the same questionnaire was again administered to HCWs. RESULTS: In both 2000 and 2004, the main motives for undergoing influenza vaccination were "hospital campaign" and "recommendation by colleagues"; the percentage of respondents who were motivated by the hospital campaign had remarkably increased from 27% in 2000 to 52% in 2004 (P<.001), whereas the percentage who were motivated by recommendation by colleagues had not changed significantly (21% vs 14%). Overall, the 4 reasons most frequently cited by HCWs for noncompliance with vaccination were insufficient available time, confidence in their health, doubt about vaccine efficacy, and fear of injection. In 2000, vaccination rates were below 30%, irrespective of occupation. After an aggressive vaccination campaign, the increase in the vaccination rate was highest among the nursing staff, increasing from 21% in 2000 to 92% in 2004, whereas the vaccination rate among the physicians was still below 60%. CONCLUSION: We conclude that a hospital campaign can markedly improve influenza vaccination rates among HCWs. Both a mobile cart system and free vaccine supply contributed to improving the vaccination rates in our study. In addition, a specifically tailored intervention strategy was required.

Protective effect of Polygonum multiflorum Thunb on amyloid beta-peptide 25-35 induced cognitive deficits in mice.

Amyloid beta protein (Abeta) may be neurotoxic during the progression of Alzheimer's disease by eliciting oxidative stress. This study was designed to determine the effect of Polygonum multiflorum Thunb water extract (PWE) on Abeta25-35-induced cognitive deficits and oxidative stress in mice. Mice were fed experimental diets comprising either 0.5 or 1% PWE for 4 weeks, and then received a single intracerebroventricular (i.c.v.) injection of Abeta25-35 (10 microg/mouse). Behavioral changes in the mice were evaluated using passive avoidance and water-maze tests. The consumption of PWE significantly ameliorated the cognitive deficits caused by i.c.v. injection of Abeta25-35. The Abeta25-35 treatment accelerated the lipid peroxidation, and PWE attenuated the Abeta-induced increase in brain levels of thiobarbituric acid reactive substances. There was an increase in glutathione peroxidase activity in PWE-treated groups. The acetylcholinesterase activity in the brain and serum was lower in PWE supplemented groups than in the only Abeta-injected group. These findings suggest that PWE exerts a preventive effect against cognitive deficits induced by Abeta25-35 accumulation in Alzheimer's disease, and that this effect is mediated by the antioxidant properties of PWE.