Vascular endothelial growth factor (VEGF) and soluble VEGF receptor FLT-1 in diabetic nephropathy

BACKGROUND

Vascular endothelial growth factor (VEGF) and its receptors have been implicated in the pathogenesis of diabetic nephropathy. The objective of this study was to determine whether alterations of the plasma and urinary VEGF and sFLT-1 levels were related to the stages and risk factors of diabetic nephropathy. In addition, we also examined the regulation of the VEGF/sFLT-1 expression by various stimuli in cultured human proximal tubule cells (HPTC).

METHODS

A total of 107 type 2 diabetic patients and 47 healthy control subjects were studied. The expression and protein levels of VEGF and sFLT-1 were measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The urinary VEGF and sFLT-1 excretions were significantly increased in the microalbuminuric and proteinuric diabetic patients. The urinary VEGF levels were positively correlated with the urinary albumin to creatinine ratio (ACR), urinary sFLT-1 levels, and negatively correlated with creatinine clearance. The urinary sFLT-1 levels also showed a positive relationship with the urinary ACR. In cultured HPTC, high glucose stimuli rapidly up-regulated VEGF synthesis without having any effect on sFLT-1 synthesis. Interestingly, angiotensin II (Ang II) induced a dose-dependent increase in the synthesis of both VEGF and sFLT-1, which was significantly blocked by losartan.

CONCLUSION

The urinary excretion of VEGF and sFLT-1 increased at a relatively early stage in diabetic nephropathy associated with urinary albumin excretion. A marked increase in both VEGF/sFLT-1 synthesis in response to Ang II was observed in HPTC, which was different from the response to glucose stimuli. These findings may imply that VEGF and sFLT-1 can actively take part in the pathogenesis of diabetic nephropathy.

Relationship between serum adiponectin concentration, pulse wave velocity and nonalcoholic fatty liver disease

OBJECTIVES

We aimed to investigate the relationship between nonalcoholic fatty liver disease (NAFLD), serum adiponectin concentration and brachial-ankle pulse wave velocity (baPWV) as a risk marker for atherosclerosis.

METHODS

A total of 213 nonalcoholic subjects (67 males, 146 females) participated in this study. Division of subjects into the NAFLD group or the normal group was based on the existence of fatty liver detected by sonography.

RESULTS

Serum adiponectin levels in the NAFLD group were significantly lower than those in the normal group. After adjusting for age, body-mass index (BMI) and the homeostasis model of assessment (HOMA), there was a significant negative correlation between NAFLD and serum adiponectin level only in females (r = -0.22, P = 0.008). Multiple logistic regression analysis showed a tendency of inverse correlation between NAFLD and serum adiponectin level in females (P = 0.055). After adjustment for age, BMI and HOMA value, serum adiponectin levels were inversely correlated with serum alanine aminotransferase (ALT) and gamma-glutamyltranspeptidase (GGT) levels (r = -0.199 (P = 0.004) and r = -0.282 (P < 0.001)). On the other hand, baPWV in the NAFLD group was also significantly higher than that in the normal group in females (P = 0.005). Individual levels of serum ALT, aspatate aminotransferase (AST), alkaline phosphatase (ALP) and GGT were positively correlated with baPWV after adjusting for age, sex, BMI, HOMA and systolic blood pressure (P < 0.05).

CONCLUSION

Serum adiponectin level and baPWV were significantly associated with NAFLD and various liver enzymes, especially in females.

Inflammation, insulin resistance, and glucose intolerance in acute myocardial infarction patients without a previous diagnosis of diabetes mellitus

We examined the prevalence of impaired glucose metabolism and its association with inflammation and insulin resistance (IR) in acute myocardial infarction (AMI) patients without a previous diagnosis of diabetes. This prospective study enrolled 52 AMI patients, and 75-g oral glucose tolerance testing was performed on 30 patients at discharge and again 3 months later. We also measured serum adiponectin, high sensitive C-reactive protein, and IL-6 on both occasions. Data were compared with those of 30 type 2 diabetic patients without a history of AMI. Forty percent and 36.7% of AMI patients had impaired glucose tolerance (IGT) at discharge and at 3 months, respectively. The corresponding proportions for newly diagnosed diabetes are 33.0% and 30.0%. At discharge, AMI patients with IGT or diabetes showed higher high sensitive C-reactive protein and IL-6 levels compared with AMI patients with normal glucose tolerance or control type 2 diabetic patients. Furthermore, AMI patients with IGT or diabetes exhibited higher IR and lower serum adiponectin levels than AMI patients with normal glucose tolerance at 3 months after discharge. Previously undiagnosed diabetes and IGT are common in Korean patients with AMI. These glycometabolic abnormalities are associated with inflammation, IR, and serum adiponectin levels.

Relationship between brachial-ankle pulse wave velocity and cardiovascular risk factors of the metabolic syndrome

In this study, we investigated the association between brachial-ankle pulse wave velocity (baPWV), a novel non-invasive means of measuring atherosclerosis, and the cardiovascular risk factors of the metabolic syndrome. The study group comprised of 368 Koreans without history of diabetes or hypertension. Anthropometric parameters, blood pressure, fasting blood glucose (FBG), lipid profiles, ankle-brachial pressure index (ABI), and baPWV were measured in each subject. ABI and baPWV levels were higher in men than in women. ABI and baPWV levels were not correlated with each other. In women, baPWV was closely associated with the cardiovascular risk factors of the metabolic syndrome. Women with the metabolic syndrome showed higher baPWV levels compared to those without the metabolic syndrome (1540 +/- 281 versus 1312 +/- 223, P < 0.001). Multiple regression analysis showed that baPWV was significantly associated with systolic blood pressure, age, sex, waist circumference, and FBG (adjusted R2 = 0.548). The present study shows that baPWV is significantly associated with the features of the metabolic syndrome in Korean women.

Plasma and urinary vascular endothelial growth factor and diabetic nephropathy in Type 2 diabetes mellitus

AIMS

Vascular endothelial growth factor (VEGF) has been implicated in the pathogenesis of diabetes mellitus. We determined whether alterations of plasma and urinary VEGF levels are related to diabetic nephropathy in Type 2 diabetic patients.

METHODS

One hundred and seven patients and 47 healthy controls were studied. Study subjects were divided into four groups using urinary albumin-to-creatinine ratio (ACR): a non-diabetic healthy control group (n = 47), a normoalbuminuric diabetic group (n = 37), a microalbuminuric diabetic group (n = 37) and an overt proteinuric diabetic group (n = 33). VEGF levels were measured by enzyme-linked immunosorbent assay.

RESULTS

(i) Urinary VEGF concentrations were significantly higher in the diabetic groups, even at the normoalbuminuric stage (log VEGF/Cr, normoalbuminuria; 4.33 +/- 1.06 vs. control; 3.53 +/- 0.79, P = 0.009). Urinary VEGF excretions increased as diabetic nephropathy advanced. (ii) Plasma and urinary VEGF levels were higher in hypertensive diabetic patients than in the normotensive individuals with diabetes. (iii) In those with diabetes, plasma VEGF levels were found to be positively correlated with plasma urea (r = 0.398, P = 0.039) and urinary ACR (r = 0.251, P = 0.044), and urinary VEGF to be positively correlated with urinary ACR (r = 0.645, P < 0.001), and creatinine (r = 0.336, P = 0.009), and to be negatively correlated with serum albumin (r = -0.557, P < 0.001). Urinary VEGF and serum creatinine were independently correlated with urinary ACR.

CONCLUSIONS

Urinary excretion of VEGF increased during the earlier stage of diabetic nephropathy and was significantly correlated with urinary albumin excretion. This suggests that urinary VEGF might be used as a sensitive marker of diabetic nephropathy and for predicting disease progression.

Declines in tobacco brand recognition and ever-smoking rates among young children following restrictions on tobacco advertisements in Hong Kong

BACKGROUND

We compared the recognition of tobacco brands and ever-smoking rates in young children before (1991) and after (2001) the implementation of cigarette advertising restrictions in Hong Kong and identified continuing sources of tobacco promotion exposure.

METHODS

A cross-sectional survey of 824 primary school children aged from 8 to 11 (Primary classes 3-4) living in two Hong Kong districts was carried out using self-completed questionnaires examining smoking behaviour and recognition of names and logos from 18 tobacco, food, drink and other brands common in Hong Kong.

RESULTS

Ever-smoking prevalence in 2001 was 3.8 per cent (1991, 7.8 per cent). Tobacco brand recognition rates ranged from 5.3 per cent (Viceroy name) to 72.8 per cent (Viceroy logo). Compared with 1991, in 2001 never-smoker children recognized fewer tobacco brand names and logos: Marlboro logo recognition rate fell by 55.3 per cent. Similar declines were also seen in ever-smoker children, with recognition of the Marlboro logo decreasing 48 per cent. Recognition rates declined amongst both boys and girls. Children from non-smoking families constituted 51 per cent (426) of the sample, whereas 34.5 per cent (284), 8.5 per cent (70), 1.7 per cent (14) and 4.4 per cent (36) of the children had one, two, three or more than three smoking family members at home, respectively. Tobacco brand recognition rates and ever-smoking prevalence were significantly higher among children with smoking family members compared with those without. Among 12 possible sources of exposure to cigarette brand names and logos, retail stalls (75.5 per cent; 622), indirect advertisements (71.5 per cent; 589) and magazines (65.3 per cent; 538) were ranked the most common.

CONCLUSION

Advertising restrictions in Hong Kong have effectively decreased primary-age children's recognition of tobacco branding. However, these children remain vulnerable to branding, mostly through exposure from family smokers, point-of-sale tobacco advertisement and occasional promotions. Action to curb these is now required.

Serum adiponectin concentrations predict the developments of type 2 diabetes and the metabolic syndrome in elderly Koreans

OBJECTIVE

To determine whether low serum adiponectin concentrations are able to predict the future developments of type 2 diabetes and the metabolic syndrome using the National Cholesterol Education Programme (NCEP) criteria. We also investigated the stability of adiponectin levels and the relationships between baseline adiponectin levels and changes in the parameters related to the metabolic syndrome over a period of 3 years.

PATIENTS AND MEASUREMENTS

This prospective cohort study included 372 elderly Koreans who participate in the SWS (South-West Seoul) study, which was conducted in 1999 and 2002 in Seoul, Korea. Fasting and postchallenge 2-h plasma glucose, body mass index (BMI), waist-to-hip ratio (WHR), blood pressure, lipid profiles and serum adiponectin data obtained in 1999 and 2002 were examined.

RESULTS

The within-person variation between 1999 and 2002 of serum adiponectin was not significant (P = 0.61). Serum adiponectin was closely correlated with the risks factors of cardiovascular disease (CVD), that is negatively with BMI, WHR, blood pressure, triglyceride and blood glucose levels, and positively with high density lipoprotein (HDL)-cholesterol levels. Subjects with the metabolic syndrome showed lower serum adiponectin concentrations than those without the metabolic syndrome (P < 0.0001). Baseline adiponectin levels were found to be correlated with subsequent changes in WHR, low density lipoprotein (LDL)-cholesterol, fasting and postload 2-h glucose over the 3-year period, after adjusting for baseline values. Multiple logistic regression analysis showed that lower baseline serum adiponectin concentrations were significantly associated with the developments of type 2 diabetes and the metabolic syndrome after adjusting for age, sex, obesity, history of impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), hypertension and dyslipidaemia.

CONCLUSIONS

Reduced concentrations of adiponectin were found to be independently associated with increased risk of both type 2 diabetes and the metabolic syndrome in elderly Koreans.

Reduced expression of peroxisome proliferator-activated receptor-alpha may have an important role in the development of non-alcoholic fatty liver disease

BACKGROUND

Although the pathogenesis of non-alcoholic fatty liver disease (NAFLD) remains poorly understood, metabolic syndrome associated with insulin resistance is the most reproducible factor in the development of NAFLD. Fat accumulation in hepatocytes results from an imbalance in the input, output and oxidation of fatty acid. Peroxisomes contain a battery of fatty acid oxidizing enzymes, the first of which, acyl-CoA oxidase (AOX), initiates the beta-oxidation spiral. One of the mammalian peroxisome proliferator-activated receptors (PPAR), PPAR-alpha, regulates the transcriptional expression of the enzymes involved in fatty acid beta-oxidation. The aim of the present study was to define the role of PPAR-alpha and AOX in the development of NAFLD using the Otsuka Long-Evans Tokushima fatty (OLETF) rat model.

METHODS

Liver tissue from OLETF (n = 12) and control (n = 10) rats 12, 28, and 40 weeks old were processed for histopathological and western blot analysis. The messenger RNA of PPAR-alpha and AOX were quantified by real-time RT-PCR.

RESULTS

At 40 weeks old, the histological analysis of the OLETF rat liver had steatosis (approximately 66%) and mild inflammation, which were comparable to those in NAFLD. Histological changes were unremarkable in 12 week and 28 week rats. In 12 week OLETF rats, the mRNA of AOX was 63% of the control. Expression of PPAR-alpha mRNA was also reduced to 3% that of the control. Along with the changes of mRNA, the protein expression of PPAR-alpha was also significantly reduced to 17% that of the control. In 28 week and 40 week animals, PPAR-alpha protein expression gradually increased to 75% and 78% that of the control. Expression of PPAR-alpha mRNA was also increased by up to 26% and 110% of the control. AOX, regulated by PPAR-alpha, also increased to 149% and 120% of the control.

CONCLUSION

Reduced expression of PPAR-alpha and AOX was observed even before definite steatosis had developed. The alteration of peroxisomal fatty acid metabolism may have an important role in the development of NAFLD.

Plant regeneration from hairy-root cultures transformed by infection with Agrobacterium rhizogenes in Catharanthus roseus

Hypocotyl explants of Catharanthus roseus produced hairy roots when cultured on Murashige and Skoog (MS) basal medium after infection by Agrobacterium rhizogenes. Explants gave rise to adventitious shoots at a frequency of up to 80% when cultured on MS medium supplemented with 31.1 microM 6-benzyladenine and 5.4 microM alpha-naphthaleneacetic acid. There was a significant difference in the frequency of adventitious shoot formation for each hairy-root line derived from a different cultivar. Plants derived from hairy roots exhibited prolific rooting and had shortened internodes. Approximately half of the plants had wrinkled leaves and an abundant root mass with extensive lateral branching, but otherwise appeared morphologically normal. Plants with hairy roots that were derived from the cultivar Cooler Apricot developed flowers with petals that were white in the proximal region, whereas the wild-type flower petals are red. PCR and Southern blot analyses revealed that plants derived from hairy roots retained the Ri TL-DNA.

Plant regeneration from hairy-root cultures transformed by infection with Agrobacterium rhizogenes in Catharanthus roseus

Hypocotyl explants of Catharanthus roseus produced hairy roots when cultured on Murashige and Skoog (MS) basal medium after infection by Agrobacterium rhizogenes. Explants gave rise to adventitious shoots at a frequency of up to 80% when cultured on MS medium supplemented with 31.1 microM 6-benzyladenine and 5.4 microM alpha-naphthaleneacetic acid. There was a significant difference in the frequency of adventitious shoot formation for each hairy-root line derived from a different cultivar. Plants derived from hairy roots exhibited prolific rooting and had shortened internodes. Approximately half of the plants had wrinkled leaves and an abundant root mass with extensive lateral branching, but otherwise appeared morphologically normal. Plants with hairy roots that were derived from the cultivar Cooler Apricot developed flowers with petals that were white in the proximal region, whereas the wild-type flower petals are red. PCR and Southern blot analyses revealed that plants derived from hairy roots retained the Ri TL-DNA.

Plasma and urinary vascular endothelial growth factor and diabetic nephropathy in Type 2 diabetes mellitus

AIMS

Vascular endothelial growth factor (VEGF) has been implicated in the pathogenesis of diabetes mellitus. We determined whether alterations of plasma and urinary VEGF levels are related to diabetic nephropathy in Type 2 diabetic patients.

METHODS

One hundred and seven patients and 47 healthy controls were studied. Study subjects were divided into four groups using urinary albumin-to-creatinine ratio (ACR): a non-diabetic healthy control group (n = 47), a normoalbuminuric diabetic group (n = 37), a microalbuminuric diabetic group (n = 37) and an overt proteinuric diabetic group (n = 33). VEGF levels were measured by enzyme-linked immunosorbent assay.

RESULTS

(i) Urinary VEGF concentrations were significantly higher in the diabetic groups, even at the normoalbuminuric stage (log VEGF/Cr, normoalbuminuria; 4.33 +/- 1.06 vs. control; 3.53 +/- 0.79, P = 0.009). Urinary VEGF excretions increased as diabetic nephropathy advanced. (ii) Plasma and urinary VEGF levels were higher in hypertensive diabetic patients than in the normotensive individuals with diabetes. (iii) In those with diabetes, plasma VEGF levels were found to be positively correlated with plasma urea (r = 0.398, P = 0.039) and urinary ACR (r = 0.251, P = 0.044), and urinary VEGF to be positively correlated with urinary ACR (r = 0.645, P < 0.001), and creatinine (r = 0.336, P = 0.009), and to be negatively correlated with serum albumin (r = -0.557, P < 0.001). Urinary VEGF and serum creatinine were independently correlated with urinary ACR.

CONCLUSIONS

Urinary excretion of VEGF increased during the earlier stage of diabetic nephropathy and was significantly correlated with urinary albumin excretion. This suggests that urinary VEGF might be used as a sensitive marker of diabetic nephropathy and for predicting disease progression.

The associations between plasma adiponectin, ghrelin levels and cardiovascular risk factors

OBJECTIVE

Ghrelin is a recently discovered peptide, which is produced primarily in the stomach. This orexigenic peptide participates not only in the induction of mealtime hunger but also in long-term body weight regulation and energy homeostasis. Adiponectin is a protein secreted by adipocytes, and has been proposed to mediate obesity-related insulin resistance. Moreover, concentrations of adiponectin are reduced in individuals with obesity, insulin resistance and cardiovascular disease. However, human data are sparse about the direct relationship between adiponectin, ghrelin and cardiovascular risk factors including insulin resistance.

DESIGN

Three hundred and thirty-eight elderly Korean women (mean age+/-s.d., 72.3+/-5.5 years) were included in the present study.

METHODS

Plasma ghrelin and adiponectin levels were measured by RIA. Anthropometric measurements were taken and a 75 g oral glucose tolerance test performed. Fasting insulin and lipid profile were measured and insulin resistance was determined using the homeostasis model assessment insulin resistance index (HOMA-R) and the quantitative insulin sensitivity check index.

RESULTS

Plasma adiponectin levels were negatively correlated with central obesity indices such as waist circumference (r=-0.27, P<0.001) and waist-to-hip ratio (WHR) (r=-0.32, P<0.001), and with insulin resistance indices such as fasting insulin (r=-0.17, P=0.004) and HOMA-R (r=-0.13, P=0.035). Plasma ghrelin levels were negatively correlated with WHR (r=-0.12, P=0.03), but plasma adiponectin and ghrelin levels were not correlated (r=0.03, P=0.66). Multiple regression analysis showed that adiponectin was associated with WHR, fasting insulin and fasting glucose levels. When ghrelin was used as a dependent variable, only WHR remained in the final fitted model.

CONCLUSION

Fasting plasma adiponectin and ghrelin levels were found to be associated with central obesity or insulin resistance. However, plasma adiponectin and ghrelin concentrations were not associated with each other in elderly Korean women.

Comparison of serum concentrations of C-reactive protein, TNF-alpha, and interleukin 6 between elderly Korean women with normal and impaired glucose tolerance

This study was performed to compare concentrations of pro-inflammatory cytokines, such as interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha) as well as acute-phase protein, such as C-reactive protein (CRP) between subjects with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT). The purpose of this study was to verify whether the pro-inflammatory cytokine-induced acute-phase response is a pathogenic mechanism in type 2 diabetes in elderly Korean women. A total of 1737 elderly subjects aged over 60 years participated in a population based study in Seoul, Korea (SWS Study 1999). Amongst them, a total of 232 non-smoking and non-diabetic female subjects aged 60-89 years was randomly selected and compared with each other. Higher serum high-sensitivity CRP (hs-CRP) concentrations were shown in subjects with IGT than those with normal glucose tolerance (median 1.2 versus 0.9, P < 0.05). Moreover, a relationship between serum hs-CRP concentrations and many components of the metabolic syndrome were detected. Serum pro-inflammatory cytokine IL-6 or TNF-alpha concentrations, however, were neither increased in subjects with IGT nor closely correlated with the components of the metabolic syndrome. In multiple regression analysis with stepwise selection method using hs-CRP as a dependent variable, it was found that white blood cell (WBC) counts, body mass index (BMI), fasting insulin, post-load 2h glucose, hematocrit and LDL cholesterol were significant independent variables. Our study confirms that increased acute-phase reaction is associated with impaired glucose tolerance and the metabolic syndrome in elderly Korean women. However, the hypothesis that pro-inflammatory cytokine-induced systemic inflammation is an early metabolic defect prior to onset of type 2 diabetes, is not supported in our study of elderly Korean women.

Modulation of the Protein Kinase Activity of mTOR

mTOR is a founding member of a family of protein kinases having catalytic domains homologous to those in phosphatidylinositol 3-OH kinase. mTOR participates in the control by insulin of the phosphorylation of lipin, which is required for adipocyte differentiation, and the two translational regulators, p70S6K and PHAS-I. The phosphorylation of mTOR, itself, is stimulated by insulin in Ser2448, a site that is also phosphorylated by protein kinase B (PKB) in vitro and in response to activation of PKB activity in vivo. Ser2448 is located in a short stretch of amino acids not found in the two TOR proteins in yeast. A mutant mTOR lacking this stretch exhibited increased activity, and binding of the antibody, mTAb-1, to this region markedly increased mTOR activity. In contrast, rapamycin-FKBP12 inhibited mTOR activity towards both PHAS-I and p70S6K, although this complex inhibited the phosphorylation of some sites more than that of others. Mutating Ser2035 to Ile in the FKBP12-rapamycin binding domain rendered mTOR resistant to inhibition by rapamycin. Unexpectedly, this mutation markedly decreased the ability of mTOR to phosphorylate certain sites in both PHAS-I and p70S6K. The results support the hypotheses that rapamycin disrupts substrate recognition instead of directly inhibiting phosphotransferase activity and that mTOR activity in cells is controlled by the phosphorylation of an inhibitory regulatory domain containing the mTAb-1 epitope.

Relation between insulin resistance and hematological parameters in elderly Koreans-Southwest Seoul (SWS) Study

In this study, we investigated the relation between insulin resistance and hematological parameters in elderly Koreans. This study included 1314 non-diabetic subjects over the age of 60, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. We measured fasting and post-load 2 h plasma glucose, insulin levels, lipid profiles, anthropometric measures, and hematological parameters. The degree of insulin resistance was assessed using the homeostasis model assessment (HOMA). We found a correlation between insulin resistance and hemoglobin concentrations in non-smoking men (r=0.20, P=0.0186). In non-smoking women, insulin resistance correlated with hemoglobin (r=0.10, P=0.0017) and with white blood cell (WBC) count (r=0.15, P=0.001). Hemoglobin concentrations and WBC counts were also associated with other components of the insulin resistance syndrome such as body mass index, blood pressure, lipid profiles and fasting plasma insulin levels (surrogate for insulin resistance). Furthermore, the group in the upper quartile for insulin resistance showed higher hemoglobin concentrations and WBC counts than the lower quartile, independent of smoking status and serum iron concentrations. Using HOMA-IR as a dependent variable in a multiple regression analysis, age, body mass index (BMI), waist-to-hip ratio (WHR), systolic blood pressure, HDL cholesterol, triglyceride, WBC count, hemoglobin, hematocrit and serum TIBC were significant. Our results provide support for a relation between insulin resistance/hyperinsulinemia and hematological parameters such as hemoglobin concentrations and WBC counts in elderly Koreans. This suggests that increased erythropoiesis and subclinical inflammation could be part of the metabolic syndrome in elderly Koreans.

Factor analysis of the metabolic syndrome among elderly Koreans--the South-west Seoul Study

AIMS

To examine the relationship between the components of the metabolic syndrome and to explore whether insulin resistance unifies the clustering of components of the metabolic syndrome among urban elderly Koreans using exploratory factor analysis.

METHODS

We included 1314 non-diabetic subjects over the age of 60 years, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. Factor analysis was carried out using the principle components analysis with Varimax orthogonal rotation of the components of the metabolic syndrome.

RESULTS

We found four major factors of cardiovascular disease risk variables in our study subjects. Impaired glucose tolerance, dyslipidaemia, hypertension and obesity aggregated as the major domain. Obesity and dyslipidaemia variables were closely related and loaded on the same factor. However, hypertension was not linked closely with other factors of the metabolic syndrome.

CONCLUSIONS

Insulin resistance is not the only contributor to the metabolic syndrome among urban elderly Koreans. Although the components of the metabolic syndrome were closely related, the finding of more than one factor suggests that more than one pathophysiological mechanism underlies full expression of the metabolic syndrome among elderly Koreans.

Comparison of ADA and WHO criteria for the diagnosis of diabetes in elderly Koreans

AIMS

This study was conducted to compare the prevalence and cardiovascular risk factors of different categories of glucose tolerance in the elderly Korean population using World Health Organization (WHO) and American Diabetes Association (ADA) criteria.

METHODS

This study included 1456 non-diabetic subjects over the age of 60 years, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. Fasting and post-challenge 2-h plasma glucose, insulin levels, body mass index (BMI), waist-hip ratio (WHR), blood pressure, and lipid profiles were examined. Prevalence of glucose tolerance categories and the level of agreement (kappa statistics) were obtained using WHO 2-h criteria and ADA fasting criteria. Comparison of cardiovascular risk factors among several concordant and discordant glucose intolerance groups was done.

RESULTS

The prevalence rates of newly diagnosed diabetes of elderly men defined by WHO 2-h criteria and ADA fasting criteria were 11.8% and 4.8%, respectively. That of elderly women was 8.1% by WHO 2-h criteria and 3.1% by ADA fasting criteria. The prevalence of impaired glucose tolerance (IGT) by WHO criteria was also higher than that of impaired fasting glucose (IFG) by ADA criteria (23.5% vs. 10.0% men, 23.7% vs. 7.5% women). The level of agreement between ADA fasting criteria and WHO 2-h criteria was low (weighted kappa = 0.228 men, weighted kappa = 0.301 women). The concordant diabetic women by both ADA fasting criteria and WHO 2-h criteria showed higher BMI, WHR, diastolic blood pressure, total cholesterol and triglyceride levels than concordant normal subjects. However, the isolated post-challenge hyperglycaemia (IPH) women group was not different significantly from the concordant normal women group except in BMI.

CONCLUSIONS

Our results clearly show that the 1997 ADA fasting criteria are less sensitive for diagnosing diabetes than oral glucose tolerance test (OGTT)-based WHO criteria in elderly Koreans. Also, there is a poor agreement of different categories of glucose tolerance between ADA and WHO criteria; therefore, the OGTT remains a valuable test in diagnosing diabetes and classifying various categories of glucose intolerance, especially in elderly Koreans.

Transmural extent of acute myocardial infarction predicts long-term improvement in contractile function

BACKGROUND

Previous animal studies have demonstrated that the transmural extent of acute myocardial infarction defined by contrast-enhanced MRI (ceMRI) relates to early restoration of flow and future improvements in contractile function. We tested the hypothesis that ceMRI would have similar predictive value in humans.

METHODS AND RESULTS

Twenty-four patients who presented with their first myocardial infarction and were successfully revascularized underwent cine and ceMRI of their heart within 7 days (scan 1) of the peak MB band of creatine kinase. Cine MRI was repeated 8 to 12 weeks later (scan 2). The transmural extent of infarction on scan 1 and wall thickening on both scans were determined using a 72-segment model. A total of 524 of 1571 segments (33%) were dysfunctional on scan 1. Improvement in segmental contractile function on scan 2 was inversely related to the transmural extent of infarction on scan 1 (P=0.001). Improvement in global contractile function, as assessed by ejection fraction and mean wall thickening score, was not predicted by peak creatine kinase-MB (P=0.66) or by total infarct size, as defined by MRI (P=0.70). The best predictor of global improvement was the extent of dysfunctional myocardium that was not infarcted or had infarction comprising <25% of left ventricular wall thickness (P<0.005 for ejection fraction, P<0.001 for mean wall thickening score).

CONCLUSION

In patients with acute myocardial infarction, the transmural extent of infarction defined by ceMRI predicts improvement in contractile function.

A case of adrenocortical tumor coexisted with paragangliomas

We report a case of adrenocortical tumor that coexisted with paragangliomas. A 35-year-old woman was admitted to the hospital because of left upper abdominal pain. A palm-sized mass was palpated at left upper quadrant. Hormonal studies revealed the features of pheochromocytoma. An emergency operation was performed because hemorrhage of the tumor was suspected. A 10 cm diameter ruptured mass was found in the left adrenal area and other tumors were also noted adjacent to inferior vena cava (IVC). The pathologic report revealed that the adrenal mass was an adrenocortical tumor with hemorrhagic necrosis and that the tumors adjacent to IVC were paragangliomas. This was the first case of adrenocortical tumor with paragangliomas in our Medline search result, hence we report the case with a review of the literature.

Presumptive mechanisms of peptic ulceration by Helicobacter pylori VacA involving mucoprotease and CagA

Helicobacter pylori vacuolating toxin (VacA) appears to be unusually stable, not only against extreme pH conditions or high temperatures, but also against common organic solvents or detergents. Under acidic conditions, its activity was markedly increased in the manner of temperature-independent, suggesting a spontaneous activation. A similar finding was also observed under alkaline conditions, however, it should have an appropriate temperature. From these observations, the mechanisms of VacA activation were suggested to be so redundant that either the case of acidic or basic amino acid residues could be involved in the VacA activation. Separately, we also found that the VacA production by H. pylori was pH-dependent: Its production was increased at a low pH region with a broad range (1.0-5.0), and at a high pH region with a narrow range (8.0-9.0). Astonishingly, a highly immunogenic CagA did not appear to be expressed under the acidic conditions. Its expression, however, was shown to be enhanced when the surrounding pH of this bacterium was raised. In contrast, mucoproteolytic activity in the H. pylori membrane was found to be increased at acidic conditions. Considering these observations, together with the stomach and duodenal pH of humans, two presumptive mechanisms of H. pylori VacA-associated ulceration may be deduced; namely, an acid- and an alkali-dependent type, involving mucoprotease and CagA, respectively.

Visualization of discrete microinfarction after percutaneous coronary intervention associated with mild creatine kinase-MB elevation

BACKGROUND

Mild elevations in creatine kinase-MB (CK-MB) are common after successful percutaneous coronary interventions and are associated with future adverse cardiac events. The mechanism for CK-MB release remains unclear. A new contrast-enhanced MRI technique allows direct visualization of myonecrosis.

METHODS AND RESULTS

Fourteen patients without prior infarction underwent cine and contrast-enhanced MRI after successful coronary stenting; 9 patients had procedure-related CK-MB elevation, and 5 did not (negative controls). The mean age of all patients was 61 years, 36% had diabetes, 43% had multivessel coronary artery disease, and all had a normal ejection fraction. Twelve patients (86%) received an intravenous glycoprotein IIb/IIIa inhibitor; none underwent atherectomy, and all had final TIMI 3 flow. Of the 9 patients with CK-MB elevation, 5 had a minor side branch occlusion during stenting, 2 had transient ECG changes, and none developed Q-waves. The median CK-MB was 21 ng/mL (range, 12 to 93 ng/mL), which is 2.3x the upper limit of normal. Contrast-enhanced MRI demonstrated discrete regions of hyperenhancement within the target vessel perfusion territory in all 9 patients. Only one developed a new wall motion abnormality. The median estimated mass of myonecrosis was 2.0 g (range, 0.7 to 12.2 g), or 1.5% of left ventricular mass (range, 0.4% to 6.0%). Hyperenhancement persisted in 5 of the 6 who underwent a repeat MRI at 3 to 12 months. No control patient had hyperenhancement.

CONCLUSIONS

Contrast-enhanced MRI provides an anatomical correlate to biochemical evidence of procedure-related myocardial injury, despite the lack of ECG changes or wall motion abnormalities. Mild elevation of CK-MB after percutaneous coronary intervention is the result of discrete microinfarction.

Fra-1 expression in malignant and benign thyroid tumor

BACKGROUND

The differential diagnosis of thyroid nodules is very important in deciding the treatment modality and the fine needle aspiration is the best diagnostic method. But, there are some limitations in use because of inadequate test materials and difficulty in interpreting. According to the study of oncogene and tumor suppressor gene about the origin of thyroid tumor, expression of Fra-1, one of AP-1 complex, is increased in thyroid neoplasm, though not present in the normal tissue. So, there is a possibility that it will be used as a method for the differential diagnosis of thyroid nodules. We tried to know whether presence or absence of Fra-1 expression can be used as a diagnostic method in differential diagnosis of thyroid nodules using the immunohistochemical (IHC) staining method.

METHODS

In 4 types of thyroid tumor that were confirmed by histologic diagnosis after operation (18 cases of adenomatous goiter, 16 cases of follicular adenoma, 30 cases of papillary cancer, 10 cases of follicular cancer), IHC staining method was performed to evaluate the expression of Fra-1.

RESULTS

In papillary and follicular thyroid cancers, the expression of Fra-1 was stronger than in benign thyroid tumor, but there was no difference in Fra-1 expression between the two types of carcinoma. Weak expression of Fra-1 was observed in all cases of follicular adenoma, though it was weaker than in carcinoma, and it was also weakly expressed only in some cases (33%) of adenomatous goiter.

CONCLUSION

The expression of Fra-1 was stronger in thyroid cancer than in benign thyroid tumor, but it was impossible to differentiate thyroid cancer from benign thyroid tumor by presence or absence of Fra-1 expression using IHC staining method.

Rapid sexing of preimplantation bovine embryo using consecutive and multiplex polymerase chain reaction (PCR) with biopsied single blastomere

The objective of this study was to establish a rapid and reliable PCR method for the sexing of 8- to 16-cell stage bovine embryos. The BOV97M and bovine 1.715 satellite DNA sequences were selected for amplification of male- and bovine-specific DNA, respectively. But the unequal number of copies of these two repetitive sequences required some modification of the multiplex PCR method. In consecutive and multiplex PCR, the first 10 PCR cycles were done with male-specific primer followed by an additional 23 cycles with bovine-specific primer. In this PCR method, the appearance of male- and bovine-specific bands was independent of the DNA concentration. This PCR method was applied successfully using groups of 8, 4, 2, and 1 blastomeres dissociated from the embryos, and the sexing efficiency was 100.0, 96.3, 94.3 and 92.1%, respectively. The coincident rate of sex determination between biopsied single blastomere and matched blastocyst was 90.0%. Therefore the developmental potential from 8- to 16-cell stage embryos to the blastocyst stage was not significantly different (P>0.2) for intact embryo (42.3%) than for demi-embryos (53.8%), suggesting that trauma to the demi-embryo caused by single-blastomere aspiration using a bevelled micropipette was very small. In conclusion, we developed a rapid (within 2 hours) and effective PCR method for the sexing of 8- to 16-cell stage bovine embryos using a single blastomere.

Serum insulin, proinsulin and proinsulin/insulin ratio in type 2 diabetic patients: as an index of beta-cell function or insulin resistance

BACKGROUND

Although insulin resistance and decreased insulin secretion are characteristics of established type 2 DM, which of these metabolic abnormalities is the primary determinant of type 2 DM is controversial. It is also not well known how insulin resistance and beta cell dysfunction influence serum insulin, proinsulin, proinsulin/insulin ratio in type 2 DM.

METHODS

We compared serum insulin, proinsulin and proinsulin/insulin ratio in type 2 diabetic patients and control subjects. We also investigated the relationship between serum insulin, proinsulin and proinsulin/insulin ratio and several biochemical markers which represent insulin resistance or beta cell function.

RESULTS

Insulin, proinsulin and proinsulin/insulin ratio were significantly higher in type 2 DM than control(p < 0.001). In diabetic patients, total insulin level was correlated with urinary albumin excretion rates(r = 0.224, p = 0.025) and body mass index(r = 0.269, p = 0.014). Proinsulin level was correlated with fasting C-peptide(r = 0.43, p = 0.002), postprandial 2 hour blood glucose(r = 0.213, p = 0.05) and triglyceride(r = 0.28, p = 0.022). Proinsulin/insulin ratio was positively correlated with fasting C-peptide(r = 0.236, p = 0.031), fasting blood glucose (r = 0.264, p = 0.015), postprandial 2 hour blood glucose(r = 0.277, p = 0.001) and triglyceride(r = 0.428, p < 0.001). In control subjects, insulin level was correlated with triglyceride(r = 0.366, p = 0.002). Proinsulin/insulin ratio was correlated with age(r = 0.241, p = 0.044).

CONCLUSION

The serum levels of insulin and proinsulin seem to be associated with several markers of insulin resistance. Whereas proinsulin/insulin ratio might represent beta cell function rather than insulin resistance. But more studies are needed to clarify the mechanisms of elevated proinsulin/insulin ratio in type 2 DM.