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Fulltext The Association between Glyceraldehyde-Derived Advanced Glycation End-Products and Colorectal Cancer Risk

Kong SY, Takeuchi M, Hyogo H, McKeown-Eyssen G, Yamagishi S, Chayama K, et al.

Cancer Epidemiol Biomarkers Prev, 2015 Dec;24(12):1855-63.
PMID: 26404963 DOI: 10.1158/1055-9965.EPI-15-0422

BACKGROUND: A large proportion of colorectal cancers are thought to be associated with unhealthy dietary and lifestyle exposures, particularly energy excess, obesity, hyperinsulinemia, and hyperglycemia. It has been suggested that these processes stimulate the production of toxic reactive carbonyls from sugars such as glyceraldehyde. Glyceraldehyde contributes to the production of a group of compounds known as glyceraldehyde-derived advanced glycation end-products (glycer-AGEs), which may promote colorectal cancer through their proinflammatory and pro-oxidative properties. The objective of this study nested within a prospective cohort was to explore the association of circulating glycer-AGEs with risk of colorectal cancer.
METHODS: A total of 1,055 colorectal cancer cases (colon n = 659; rectal n = 396) were matchced (1:1) to control subjects. Circulating glycer-AGEs were measured by a competitive ELISA. Multivariable conditional logistic regression models were used to calculate ORs and 95% confidence intervals (95% CI), adjusting for potential confounding factors, including smoking, alcohol, physical activity, body mass index, and diabetes status.
RESULTS: Elevated glycer-AGEs levels were not associated with colorectal cancer risk (highest vs. lowest quartile, 1.10; 95% CI, 0.82-1.49). Subgroup analyses showed possible divergence by anatomical subsites (OR for colon cancer, 0.83; 95% CI, 0.57-1.22; OR for rectal cancer, 1.90; 95% CI, 1.14-3.19; Pheterogeneity = 0.14).
CONCLUSIONS: In this prospective study, circulating glycer-AGEs were not associated with risk of colon cancer, but showed a positive association with the risk of rectal cancer.
IMPACT: Further research is needed to clarify the role of toxic products of carbohydrate metabolism and energy excess in colorectal cancer development.

Matched MeSH terms: Glycosylation End Products, Advanced/blood*
Fulltext An enzyme immunoassay for advanced glycosylation end-products in serum

Wan Nazaimoon WM, Khaid BAK

Malays J Pathol, 1998 Dec;20(2):83-9.
PMID: 10879267

We successfully developed an in-house, competitive enzyme immunoassay to measure advanced glycosylation end-products (AGE) in serum. The assay involved coating microtitre wells with AGE-BSA at 8 micrograms/ml for 4 hours, followed by overnight incubation of 20 microliters sample (prediluted at 1:6) with 80 microliters antiserum (1:8000). HRP-labelled goat anti-rabbit was used as the second antibody and 3,5',5,5'-tetramethylbenzidine dihydrochloride as the substrate. Incubation was carried out at 4 degrees C. As suggested in an earlier study, we standardised the AGE units against normal human serum (NHS). Thus, one AGE unit was defined as the inhibition that resulted when the 1:6 diluted NHS was assayed. Mean (+/- SD) AGE level in normal subjects (n = 37) was significantly lower than in diabetes subjects with microalbuminuria (n = 57) (6.0 +/- 0.7 versus 10.2 +/- 4.7 units/ml, p = 0.0001). With the availability of in-house assay and by standardising the AGE unit with the other laboratories, more studies could be undertaken and results compared, and possibly, further elucidate the roles of AGE in the pathogenesis of diabetic complications.

Matched MeSH terms: Glycosylation End Products, Advanced/blood*
Comparison of oxidative damage in Malaysian end-stage renal disease patients with or without non-insulin-dependent diabetes mellitus

Kuppusamy UR, Indran M, Ahmad T, Wong SW, Tan SY, Mahmood AA

Clin Chim Acta, 2005 Jan;351(1-2):197-201.
PMID: 15563890 DOI: 10.1016/j.cccn.2004.09.014

BACKGROUND: Comparisons of oxidative indices and total antioxidant status between end-stage renal disease (ESRD) patients with or without diabetes is scant, especially in the Asian population.
METHOD: The assays were carried out according to known established protocols.
RESULT: The present study showed that ESRD patients with or without non-insulin-dependent diabetes mellitus (NIDDM) did not have any significant differences in antioxidant enzyme activities, advanced glycated end products (AGE), advanced oxidized protein products (AOPP) and ferric reducing ability of plasma (FRAP), indicating that hyperglycemia does not exacerbate oxidative damage in ESRD. The regulation of catalase and glutathione peroxidase is also altered in ESRD. Elevated FRAP was observed in both ESRD groups (with and without NIDDM). The dialysis process did not alter the antioxidant enzyme activities but decreased AGEs and FRAP and increased AOPP levels.
CONCLUSION: Oxidative stress is present in ESRD but this is not significantly exacerbated by hyperglycemia. The contribution of components in the pathology of renal failure towards oxidative stress exceeds that of hyperglycemia.

Matched MeSH terms: Glycosylation End Products, Advanced/blood
Effect of Tai Chi exercise on DNA damage, antioxidant enzymes, and oxidative stress in middle-age adults

Goon JA, Aini AH, Musalmah M, Anum MY, Nazaimoon WM, Ngah WZ

J Phys Act Health, 2009 Jan;6(1):43-54.
PMID: 19211957

BACKGROUND: The biochemical mechanisms involving oxidative stress to explain the relationship between exercise and healthy aging are still unclear.
METHODS: Tai Chi participants and matched sedentary volunteers age 45 and above were enrolled. Glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities; levels of DNA damage using the comet assay; and malondialdehyde (MDA) and advanced glycation end products (AGE) were determined at 0, 6, and 12 months.
RESULTS: Tai Chi subjects had decreased normal and increased mildly damaged DNA with elevated GPx activity after 6 months (n=25). Plasma MDA and AGE concentrations decreased significantly after 12 months (n=15) accompanied by increased SOD activity. This may be attributed to the hormesis effect, whereby mild induction of oxidative stress at the first 6 months of exercise resulted in stimulation of antioxidant defenses. These parameters were unchanged in the sedentary subjects in the first 6 months (n=27) except for elevated SOD activity. After 12 months, the sedentary subjects (n=17) had decreased normal DNA and increased severely damaged DNA with unaltered MDA and AGE levels while SOD and GPx activities were significantly elevated.
CONCLUSION: Regular Tai Chi exercise stimulated endogenous antioxidant enzymes and reduced oxidative damage markers.

Matched MeSH terms: Glycosylation End Products, Advanced/blood
Improvement in C-reactive protein and advanced glycosylation end-products in poorly controlled diabetics is independent of glucose control

Md Isa SH, Najihah I, Nazaimoon WM, Kamarudin NA, Umar NA, Mat NH, et al.

Diabetes Res Clin Pract, 2006 Apr;72(1):48-52.
PMID: 16253380 DOI: 10.1016/j.diabres.2005.09.011

We studied the efficacy of four different treatment regimens (sulphonylurea and metformin+/-acarbose versus glimepiride and rosiglitazone versus glimepiride and bedtime NPH insulin versus multiple actrapid and NPH insulin injections) in poorly controlled type 2 diabetes subjects on hs-CRP, VCAM-1 and AGE at 4, 8 and 12 weeks of treatment. Multiple insulin injections rapidly improved HbA(1c) by 0.6+/-0.9% (p<0.005), 1.2+/-1.3% (p<0.0005) and 1.3+/-1.4% (p<0.0005) at week 4, at week 8 and week 12, respectively. Subjects who continued their existing combination treatment of sulphonylurea, metformin+/-acarbose also showed a significant reduction in HbA(1c) (p<0.05). Although effective in reducing glycemic parameters, there was no reduction in CRP levels in either treatment group. The treatment regimen consisting of rosiglitazone and glimepiride significantly lowered hs-CRP by -2.6 (3.9) mg/L (p<0.05) at week 12 in spite of no improvement in blood glucose. AGE improved in all groups irrespective of type of treatment, glycaemic control and CRP levels. Our data indicate rapid glycaemic control alone does not necessarily result in improvement in markers of inflammation in type 2 diabetes patients.

Matched MeSH terms: Glycosylation End Products, Advanced/blood*
Fulltext The effects of short-term, rapid glycemic control on the peroneal nerve function and serum VCAM-1 and AGE in type 2 diabetic patients in Malaysia

Norlinah MI, Hamizah R, Md Isa SH, Wan Nazaimoon WM, Khalid BA

Indian J Med Sci, 2009 Apr;63(4):131-8.
PMID: 19414982

BACKGROUND: The role of endothelial injury and circulating adhesion molecule in the development and progression of diabetic peripheral neuropathy in the long-term has been established previously.
AIMS: To study the effects of short-term glycemic control using insulin and oral hypoglycemic agent therapy (OHA) on the peroneal nerve function and vascular cell adhesion molecule-1 (VCAM-1) and advanced glycation endproducts (AGE) levels in type 2 diabetic patients.
SETTINGS AND DESIGN: A randomized controlled study involving poorly controlled (HbA1c, 7.5%-11%) type 2 diabetic patients attending the endocrinology outpatient center in a tertiary hospital in Kuala Lumpur.
MATERIALS AND METHODS: Twenty-nine patients were randomized to receive insulin (n=15) or OHA (n=14) for 8 weeks. The glycemic variables (HbA1c, fasting plasma glucose [FPG], fructosamine), VCAM-1, serum AGE and the peroneal motor conduction velocity (PMCV) were measured at baseline and at 4-week intervals.
STATISTICAL ANALYSIS USED: Paired 't' test or Kruskal Wallis test; and the unpaired 't' test or Mann-Whitney U test were used for within-group and between-group analyses, respectively. Correlation was analyzed using Spearman's correlation coefficient.
RESULTS: Within-group analysis showed significant progressive improvement in HbA1c at weeks 4 and 8 in the insulin group. The PMCV improved significantly in both groups by week 8, and by week 4 (P = 0.01) in the insulin group. PMCV correlated negatively with VCAM-1 (P = 0.031) and AGE (P = 0.009) at week 8.
CONCLUSION: Aggressive glycemic control with insulin improves the peroneal nerve function within 4 weeks. Improvement in the serum VCAM-1 and AGE levels correlated significantly with improvement in peroneal nerve conduction velocity only in the insulin group.
Study site: Tertiary endocrinology outpatient center in Kuala Lumpur, Malaysia

Matched MeSH terms: Glycosylation End Products, Advanced/blood
Ethnic disparity in central arterial stiffness and its determinants among Asians with type 2 diabetes

Zhang X, Liu JJ, Sum CF, Ying YL, Tavintharan S, Ng XW, et al.

Atherosclerosis, 2015 Sep;242(1):22-8.
PMID: 26162317 DOI: 10.1016/j.atherosclerosis.2015.06.019

OBJECTIVE: We previously reported ethnic disparity in adverse outcomes among Asians with type 2 diabetes (T2DM) in Singapore. Central arterial stiffness can aggravate systemic vasculopathy by propagating elevated systolic and pulse pressures forward, thereby accentuating global vascular injury. We aim to study ethnic disparity in central arterial stiffness and its determinants in a multi-ethnic T2DM Asian cohort.
METHODS: Arterial stiffness was estimated by carotid-femoral pulse wave velocity (PWV) and augmentation index (AI) using applanation tonometry method in Chinese (N = 1045), Malays (N = 458) and Indians (N = 468). Linear regression model was used to evaluate predictors of PWV and AI.
RESULTS: PWV was higher in Malays (10.1 ± 3.0 m/s) than Chinese (9.7 ± 2.8 m/s) and Indians (9.6 ± 3.1 m/s) (P = 0.018). AI was higher in Indians (28.1 ± 10.8%) than Malays (25.9 ± 10.1%) and Chinese (26.1 ± 10.7%) (P < 0.001). Malays remain associated with higher PWV (β = 0.299, P = 0.048) post-adjustment for age, gender, duration of diabetes, hemoglobin A1c, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), soluble receptor for advanced glycation end-products, urinary albumin-to-creatinine ratio, and insulin usage, which were all independent predictors of PWV. Indians remain associated with higher AI (β = 2.776, P < 0.001) post-adjustment for age, gender, BMI, SBP, DBP, and height, which were independent predictors of AI. These variables explained 27.7% and 33.4% of the variance in PWV and AI respectively.
CONCLUSIONS: Malays and Indians with T2DM have higher central arterial stiffness, which may explain their higher risk for adverse outcomes. Modifying traditional major vascular risk factors may partially alleviate their excess cardiovascular risk through modulating arterial stiffness.
KEYWORDS: Arterial stiffness; Augmentation index; Pulse wave velocity; Type 2 diabetes

Matched MeSH terms: Glycosylation End Products, Advanced/blood