DNA damage and cytotoxicity in adult subjects with prediabetes

Integrating machine learning and single-cell sequencing to identify shared biomarkers in type 1 diabetes mellitus and clear cell renal cell carcinoma

Purpose

Type 1 diabetes mellitus (T1DM), as an autoimmune disease, can increase susceptibility to clear cell renal cell carcinoma (ccRCC) due to its proinflammatory effects. ccRCC is characterized by its subtle onset and unfavorable prognosis. Thus, the aim of this study was to highlight prevention and early detection opportunities in high-risk populations by identifying common biomarkers for T1DM and ccRCC.

Methods

Based on multiple publicly available datasets, WGCNA was applied to identify gene modules closely associated with T1DM, which were then integrated with prognostic DEGs in ccRCC. Subsequently, the LASSO and SVM algorithms were employed to identify shared hub genes between the two diseases. Additionally, clinical samples were used to validate the expression patterns of these hub genes, and scRNA-seq data were utilized to analyze the cell types expressing these genes and to explore potential mechanisms of cell communication.

Results

Overall, three hub genes (KIF21A, PIGH, and RPS6KA2) were identified as shared biomarkers for TIDM and ccRCC. Analysis of clinical samples and multiple datasets revealed that KIF21A and PIGH were significantly downregulated and that PIG was upregulated in the disease group. KIF21A and PIGH are mainly expressed in NK and T cells, PRS6KA2 is mainly expressed in endothelial and epithelial cells, and the MIF signaling pathway may be related to hub genes.

Conclusion

Our results demonstrated the pivotal roles of hub genes in T1DM and ccRCC. These genes hold promise as novel biomarkers, offering potential avenues for preventive strategies and the development of new precision treatment modalities.

Transitions in metabolic syndrome and metabolic obesity status over time and risk of urologic cancer: A prospective cohort study

BACKGROUND AND AIMS

The effects of metabolic obesity (MO) phenotypes status and their dynamic changes on urologic cancer (UC) is ignored. We aimed to investigate the association between metabolic syndrome (MetS) and MO status at baseline, their dynamic changes and UC risk.

METHODS

This paper studied 97,897 subjects who were free of cancers at baseline (2006-2007). Individuals were classified into four MO phenotypes by MetS and obesity at baseline. Transitions in MetS and MO status from 2006-2007 to 2008-2009 were considered. The hazard ratios (HRs) and 95% confidence intervals (CIs) for UC were assessed by multifactorial Cox proportional risk regression models. The main limitations of this study are as follows: the ratio of men to women in the cohort is unbalanced; the impacts of MetS and MO on each cancer type (kidney cancer, prostate cancer, bladder cancer) have not been analyzed separately; the transition intervals of MetS and MO phenotypes are relatively short.

RESULTS

From baseline (2006-2007) survey to December 31, 2020, during a median follow-up of 14.02 years, 554 cases of UC were diagnosed. Participants with MetS [HRs (95% CI) = 1.26 (1.06-1.49)] and metabolically unhealthy obesity (MUO) [HRs (95% CI) = 1.49 (1.17-1.89)] had significantly higher risk of UC than those with non-MetS and metabolically healthy normal weight (MHN). Transitions in MetS and MO phenotypes over time were studied. Compared with non-MetS to non-MetS, the risks for UC in MetS to MetS [HRs (95% CI) = 1.45 (1.11-1.88)] was increased. Compared with MHN to MHN, both MUO to metabolically healthy obesity (MHO) [HRs (95% CI) = 2.65 (1.43-4.92)] and MUO to MUO [HRs (95% CI) = 1.60 (1.06-2.42)] had significantly higher UC risk.

CONCLUSIONS

MetS and MUO increased the UC risk at baseline. Transitions of MetS to MetS, MUO to MUO and even MUO to MHO over time significantly increased the risk of UC development.

Cumulative exposure to impaired fasting glucose and gastrointestinal cancer risk: A nationwide cohort study

BACKGROUND

Impaired fasting glucose (IFG) is associated with the risk of various cancers, but the cumulative effect of IFG on gastrointestinal cancer risk remains unclear. This study evaluated the association between the cumulative exposure to IFG and gastrointestinal cancer risk.

METHODS

The authors extracted data from the Korean National Health Insurance Service and health examination data sets. Among individuals ≥40 years old who were free of diabetes or cancer, 1,430,054 who underwent national health examinations over 4 consecutive years from 2009 to 2012 were selected and followed up until gastrointestinal cancer diagnosis, death, or December 31, 2019. The IFG exposure score (range, 0-4) was based on the number of IFG diagnoses over 4 years.

RESULTS

The median follow-up duration was 6.4 years. Consistent normoglycemia for 4 years was found in 44.3% of the population, whereas 5.0% had persistent IFG and 50.7% had intermittent IFG. Compared to the group with an IFG exposure score of 0, groups with IFG exposure scores of 1, 2, 3, and 4 had a 5%, 8%, 9%, and 12% increased risk of gastrointestinal cancer, respectively (score 1: adjusted hazard ratio [aHR], 1.05; 95% confidence interval [CI], 1.01-1.08; score 2: aHR, 1.08; 95% CI, 1.04-1.12; score 3: aHR, 1.09; 95% CI, 1.05-1.14; score 4: aHR, 1.12; 95% CI, 1.06-1.19). Persistent IFG exposure was also associated with higher risks of individual cancer types (colorectum, stomach, pancreas, biliary tract, and esophagus).

CONCLUSIONS

Cumulative exposure to IFG is associated with an increased risk of developing gastrointestinal cancer, in a dose-dependent manner.

PLAIN LANGUAGE SUMMARY

Hyperglycemia, including both diabetes and prediabetes, has been associated with an increased risk of various cancers. However, the cumulative effect of impaired fasting glucose on the risk of developing gastrointestinal cancer remains unclear. A frequent diagnosis of impaired fasting glucose was dose-dependently associated with a higher risk of developing overall gastrointestinal cancer. Furthermore, risks of individual cancer types increased with persistent impaired fasting glucose. Early detection of hyperglycemia and strict glycemic control can lower the risk of gastrointestinal cancer by reducing hyperglycemic burden. Additionally, for some individuals, lifestyle changes such as managing metabolic syndrome or abstaining from alcohol may also be helpful.

Cancer risk according to fasting blood glucose trajectories: a population-based cohort study

INTRODUCTION

Diabetes mellitus is known to increase the risk of cancer. Fasting blood glucose (FBG) levels can be changed over time. However, the association between FBG trajectory and cancer risk has been insufficiently studied. This research aims to examine the relationship between FBG trajectories and cancer risk in the Korean population.

RESEARCH DESIGN AND METHODS

We analyzed data from the National Health Insurance Service-National Health Screening Cohort collected between 2002 and 2015. Group-based trajectory modeling was performed on 256,271 Koreans aged 40-79 years who had participated in health examinations at least three times from 2002 to 2007. After excluding patients with cancer history before 2008, we constructed a cancer-free cohort. The Cox proportional hazards model was applied to examine the association between FBG trajectories and cancer incidence by cancer type, after adjustments for covariates. Cancer case was defined as a person who was an outpatient thrice or was hospitalized once or more with a cancer diagnosis code within the first year of the claim.

RESULTS

During the follow-up time (2008-2015), 18,991 cancer cases were identified. Four glucose trajectories were found: low-stable (mean of FBG at each wave <100 mg/dL), elevated-stable (113-124 mg/dL), elevated-high (104-166 mg/dL), and high-stable (>177 mg/dL). The high-stable group had a higher risk of multiple myeloma, liver cancer and gastrointestinal cancer than the low-stable group, with HR 4.09 (95% CI 1.40 to 11.95), HR 1.68 (95% CI 1.25 to 2.26) and HR 1.27 (95% CI 1.11 to 1.45), respectively. In elevated-stable trajectory, the risk increased for all cancer (HR 1.08, 95% CI 1.02 to 1.16) and stomach cancer (HR 1.24, 95% CI 1.07 to 1.43). Significant associations were also found in the elevated-high group with oral (HR 2.13, 95% CI 1.01 to 4.47), liver (HR 1.50, 95% CI 1.08 to 2.08) and pancreatic cancer (HR 1.99, 95% CI 1.20 to 3.30).

CONCLUSIONS

Our study highlights that the uncontrolled high glucose level for many years may increase the risk of cancer.

Association of metabolic syndrome and its components with the risk of urologic cancers: a prospective cohort study

OBJECTIVE

To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing urologic cancers.

METHODS

This study included 101,510 observation subjects from May 2006 to December 2007. The subjects received questionnaires and were subjected to clinical and laboratory examinations to collect data on baseline population characteristics, waist circumference (WC), blood pressure (BP), blood glucose, blood lipids, lifestyle, and past disease history. Finally, follow-up was conducted from the date of recruitment to December 31, 2019. Cox proportional hazards modelling was applied to analyze the association between MetS and its components and the risk of developing urologic cancers.

RESULTS

A total of 97,975 observation subjects met the inclusion criteria. The cumulative follow-up period included 1,209,178.65 person-years, and the median follow-up time was 13.03 years. During the follow-up period, 485 cases of urologic cancers (165 cases of kidney cancer, 134 cases of prostate cancer, 158 cases of bladder cancer, and 28 cases of other urologic cancers) were diagnosed. The log-rank test results for the cumulative incidences of urologic cancer, kidney cancer, and prostate cancer indicated significant (P < 0.01) differences between the MetS and non-MetS groups (0.70% vs. 0.48%, 0.27% vs. 0.15%, and 0.22% vs. 0.13%, respectively). Compared to the non-MetS group, the risk of developing urologic [HR (95% CI) = 1.29 (1.08-1.55)], kidney [HR (95% CI) = 1.74 (1.28-2.37)], and prostate [HR (95% CI) = 1.47 (1.04-2.07)] cancers was significantly higher in the MetS group. In the MetS group, elevated BP increased the risk of developing of urologic cancer [HRs (95% CI) = 1.35 (1.10-1.66)] and kidney cancer [HR (95% CI) = 1.74 (1.21-2.51)], while central obesity increased the risk of developing prostate cancer [HR (95% CI) = 1.68 (1.18-2.40)].

CONCLUSIONS

MetS increased the risk of developing urologic, kidney, and prostate cancers but had no association with the development of bladder cancer.

Association Between Glycemic Status and the Risk of Kidney Cancer in Men and Women: A Nationwide Cohort Study

OBJECTIVE

Kidney cancer predominantly affects men, suggesting a biological protection against kidney cancer in women. We investigated the dose-response association between glycemic status and kidney cancer risk in men and women.

RESEARCH DESIGN AND METHODS

In this nationwide cohort study, 9,492,331 adults without cancer who underwent national health screening in 2009 were followed up until 31 December 2018. We estimated kidney cancer risk using multivariable Cox proportional hazard regression models after adjusting for potential confounders.

RESULTS

During the 78.1 million person-years of follow-up, incident kidney cancer occurred in 8,834 men and 3,547 women. The male-to-female ratio of the incidence rate was 2.1:1 in never-smokers with normoglycemia (17.8 vs. 8.5/100,000 person-years). Among never-smokers, men with diabetes, but not prediabetes, had an increased risk of kidney cancer (adjusted hazard ratio [aHR] 1.25 [95% CI 1.12-1.38] and 1.06 [0.97-1.15], respectively). Among never-smokers, women with both diabetes and prediabetes had an increased risk (aHR 1.34 [95% CI 1.21-1.49] and 1.19 [1.10-1.29], respectively) (Ptrend <0.01). Among smokers, men and women with diabetes had 49% and 85% increased kidney cancer risk (aHR 1.49 [95% CI 1.37-1.61] and 1.85 [1.26-2.73], respectively).

CONCLUSIONS

Glycemic status and kidney cancer risk exhibited a dose-response association in women. Diabetes, but not prediabetes, was associated with an increased risk in men. Although women have a lower risk of kidney cancer than men, women with even prediabetes have an increased risk. These findings should not be overlooked when monitoring for kidney complications.

Associations between serum glucose, insulin, insulin resistance and the risk of incident primary liver cancer or chronic liver disease mortality: a nested case-control study

BACKGROUND

To evaluate the associations between pre-diagnostic levels of serum insulin, glucose and insulin resistance (HOMA-IR) and future risk of incident primary liver cancer (PLC) or chronic liver disease (CLD)-related mortality.

METHODS

We used a nested case-control design to evaluate subjects over 22 years of follow-up. Glucose, insulin, and three markers of hepatitis B virus (HBV) and hepatitis C virus were measured in fasting baseline serum from 119 incident PLCs, 157 CLD-death cases and 512 matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression to estimate the associations between insulin, glucose, HOMA-IR and the risk of PLC or CLD death.

RESULTS

Compared with the lowest quartile of insulin, multivariable adjusted models showed that subjects in the highest quartile had elevated odds of developing PLC (ORQ4/Q1 = 2.42, 95% CI = 1.26-4.75, Ptrend = 0.007), particularly in HBV-positive subjects (Pinteraction = 0.040), and of CLD death (ORQ4/Q1 = 1.80, 95% CI = 1.02-3.21, Ptrend = 0.018). For glucose, in the HBV-positive group, subjects in the fourth quartile had an increased risk of PLC (ORQ4/Q1 = 2.18, 95% CI = 1.07-4.60, Ptrend = 0.009), and of CLD mortality (ORQ4/Q1 = 1.75, 95% CI = 0.95-3.28, Ptrend = 0.019). Subjects with the highest HOMA-IR values had a threefold risk of developing PLC (ORQ4/Q1 = 2.94, 95% CI = 1.54-5.87, Ptrend = 0.001), and a twofold risk of CLD death (ORQ4/Q1 = 2.20, 95% CI = 1.25-3.94, Ptrend = 0.005).

CONCLUSIONS

We found that serum insulin and HOMA-IR could potentially be risk factors for PLC or CLD death.

Iron supplementation does not aggravate impaired glucose tolerance and sugar overload-induced genotoxicity in rats

High sugar intake is a major risk factor for metabolic disorders. Genotoxicity is an important factor in diabetes onset, and iron (Fe) may be an aggravating element. However, this relationship is still poorly established. Thus, this study evaluated whether Fe supplementation could aggravate obesity, impaired glucose tolerance, and sugar overload-induced genotoxicity in rats. A total of 24 rats were treated with different diets: standard diet (SD, n = 8), invert sugar overload (320 g/L, HSD, n = 8), or Fe plus invert sugar overload (2.56 mg/L of Fe²⁺, Fe-HSD, n = 8) for four months. After treatment, the Fe-HSD group showed no excessive weight gain or impaired glucose tolerance. DNA damage in blood, as assessed by comet assay, gradually increased in HSD during treatment (p < 0.001), whereas Fe-HSD showed a nonlinear increase in DNA damage. Moreover, Fe-HSD presented 0.6-fold more DNA damage compared with SD (p = 0.0055) in the 1st month of treatment. At months 2 and 3, results show a ≥ 1.4-fold increase in HSD and Fe-HSD DNA damage, respectively, compared with SD (p < 0.01). At the end of the experiment, only HSD DNA damage differed from SD (1.5-fold more, p = 0.0196). Fe supplementation did not aggravate the invert sugar-induced DNA damage (p > 0.05). In the pancreas, results showed no differences in DNA damage. Mutagenicity, evaluated by micronucleus testing, was not observed regardless of treatment (p = 0.428). Fe supplementation, in the evaluated concentration, did not aggravate weight gain, impaired glucose tolerance, and sugar overload-induced genotoxicity in rats.

Potential Ameliorative Effects of Chromium Supplementation on Glucose Metabolism, Obesity, and Genomic Stability in Prediabetic Rat Model

Chromium (III) (Cr(III)) effect on improving glucose, body mass loss, and genomic stability has been extensively studied in models of type 2 diabetes. However, there is a lack of studies evaluating its effect on prediabetes. Thus, this study evaluates the effects of Cr(III) as dietetic supplementation on glucose metabolism, obesity, and genomic stability on prediabetic rat model using high-invert sugar. Male Wistar rats were divided randomly into four treatment groups: (1) control, receiving standard diet (control); (2) prediabetic (PD), receiving a 32% of invert sugar; (3) Cr(III), receiving chromium (III) chloride (CrCl₃•6H₂O) (58.4 mg/L); and (4) Cr(III) + PD, receiving CrCl₃•6H₂O in combination with high-invert sugar. Cr(III) supplementation significantly reduced blood glucose (123.00 ± 8.29 mg/dL vs. 115.30 ± 9.31 mg/dL, p = 0.015) and partially reduced area under the 120-min blood glucose response curve (AUC) in PD rats (p = 0.227). Moreover, Cr(III) attenuated weight gain (187.29 ± 38.56 g vs. 167.22 ± 29.30 g, p = 0.004), significantly reducing body mass index (0.68 ± 0.04 g/cm² vs. 0.63 ± 0.04 g/cm², p < 0.001), Lee index (0.30 ± 0.01 vs. 0.28 ± 0.01, p < 0.001), and peritoneal fat (p < 0.001). Regarding genomic stability, high-invert sugar, Cr(III), or the combination of both did not produce changes in oxidative stress, DNA damage in pancreas, or cytotoxicity markers. These data suggest that Cr(III) supplementation improved partially glucose metabolism and reduced obesity in rat model PD due to high-invert sugar without influence in genomic stability.

Dietary sugars and related endogenous advanced glycation end-products increase chromosomal DNA damage in WIL2-NS cells, measured using cytokinesis-block micronucleus cytome assay

This study investigated the effect of glucose and fructose, and advanced glycation end-products (AGEs) on genome damage in WIL2-NS cells, measured using the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. The effect of AGEs was investigated using the bovine serum albumin (AGE-BSA) model system induced either with glucose (Glu-BSA) or with fructose (Fru-BSA). Liquid chromatography-mass spectrometry (LC-MS/MS) analysis showed higher Nε-carboxymethyllysine (CML; 26.76 ± 1.09 nmol/mg BSA) levels in the Glu-BSA model. Nε-Carboxyethyllysine (CEL; 7.87 ± 0.19 nmol/mg BSA) and methylglyoxal-derived hydroimidazolone-1 (MG-H1; 69.77 ± 3.74 nmol/mg BSA) levels were higher in the Fru-BSA model. Genotoxic effects were measured using CBMN-Cyt assay biomarkers [binucleated(BN) cells with micronuclei (MNi), BN with nucleoplasmic bridges (NPBs) and BN with nuclear buds (NBuds)] following 9 days of treatment with either glucose, fructose, Glu-BSA or Fru-BSA. Fructose treatment exerted a significant genotoxic dose-response effect including increases of BN with MNi (R2 = 0.7704; P = 0.0031), BN with NPBs (R2 = 0.9311; P < 0.0001) and BN with NBuds (R2 = 0.7118; P = 0.0091) on cells, whereas the DNA damaging effects of glucose were less evident. High concentrations of AGEs (400-600 µg/ml) induced DNA damage; however, there was no effect on cytotoxicity indices (necrosis and apoptosis). In conclusion, this study demonstrates a potential link between physiologically high concentrations of reducing sugars or AGEs with increased chromosomal damage which is an important emerging aspect of the pathology that may be induced by diabetes. Ultimately, loss of genome integrity could accelerate the rate of ageing and increase the risk of age-related diseases over the long term. These findings indicate the need for further research on the effects of glycation on chromosomal instability and to establish whether this effect is replicated in humans in vivo.

The association between fasting blood glucose trajectory and cancer risk in Chinese population without diabetes

To examine the associations between fasting blood glucose (FBG) trajectories, the changes in FBG over time and the risk of cancer, particularly for gastrointestinal cancer, we enrolled 69,742 participants without diabetes from the Kailuan cohort. FBG trajectories (2006-2010) were modeled by group-based trajectory modeling, and five trajectories were identified: low-increasing (n = 6,275), moderate-stable (n = 44,120), moderate-increasing (n = 10,149), elevated-decreasing (n = 5,244) and elevated-stable (n = 3,954). A total of 1,364 cancer cases were accumulated between 2010 and 2015, including 472 gastrointestinal cancer cases. We used Cox proportional hazards regression models to evaluate the associations between FBG trajectory patterns and the risk of cancer. We further assessed the associations while carefully controlling for initial body mass index (BMI) in 2006 and for changes in BMI during 2006-2010. Relative to the moderate-stable group, we found a higher hazard ratio (HR) for overall cancer in the low-increasing group (HR = 1.26, 95% confidence interval (CI) 1.06-1.50); and for gastrointestinal cancer in the elevated-stable group (HR = 1.66, 95% CI 1.22-2.26). Moreover, among participants with an initial BMI ≥25 kg/m² , a positive association with the low-increasing group was observed for both overall cancer and gastrointestinal cancer (HR = 1.54, 95% CI 1.17-2.04; HR = 1.65, 95% CI 1.02-2.66; respectively); among participants with a stable BMI (4.40% loss-5.15% gain), a positive association with the elevated-stable group was observed both for overall cancer and gastrointestinal cancer (HR = 1.43, 95% CI 1.10-1.87; HR = 1.95, 95% CI 1.33-2.86; respectively). Our study observed that FBG trajectories were associated with cancer risk among participants without diabetes, and BMI may modify the associations.

Postoperative Fasting Blood Glucose Predicts Prognosis in Stage I-III Colorectal Cancer Patients Undergoing Resection

PURPOSE

The relationship between high blood glucose and colorectal cancer (CRC) has been studied, but the role of postoperative fasting blood glucose (FBG) in patients with a prior normal FBG has never been addressed.

METHODS

A total of 120 CRC patients staged I-III were enrolled, and the prognostic value of postoperative FBG for disease-free survival (DFS) was determined by Kaplan-Meier analysis. Univariate and multivariate analyses were conducted to test other clinicopathological parameters, including preoperative hemoglobin (HGB) and the neutrophil-lymphocyte ratio (NLR).

RESULTS

By a cut-off point of 5.11 mmol/L, 51 and 69 patients were divided into low postoperative FBG (<5.11 mmol/L) and high postoperative FBG (≥5.11 mmol/L) groups, respectively. A high postoperative FBG was more common in older age (P = 0.01), left-located tumor (P = 0.02), smaller tumor diameter (P = 0.01), node negative involvement (P = 0.01), lesser positive lymph nodes (P = 0.02), and high preoperative HGB (P = 0.01). Further, high postoperative FBG patients displayed a significantly better DFS than low postoperative FBG patients (48.80 ± 22.12 months vs. 40.06 ± 24.36 months, P = 0.04), but it was less likely to be an independent prognostic factor.

CONCLUSIONS

Postoperative FBG plays a temporal prognostic role for patients with stage I-III CRC with a prior normal FBG, but it is not an independent prognostic factor.

Diabetic encephalopathy: beneficial effects of supplementation with fatty acids ω3 and nordihydroguaiaretic acid in a spontaneous diabetes rat model

Background

Diabetic encephalopathy is a chronic complications of diabetes mellitus that affects the central nervous system. We evaluated the effect of ω3 and ω6 polyunsaturated fatty acids (PUFAs) supplementation plus the antioxidant agent nordihydroguaiaretic acid (NDGA) on the etiopathology of diabetic encephalopathy in eSS rats, a spontaneous model of type 2 diabetes.

Methods

One hundred twenty spontaneous diabetic eSS male rats and 38 non-diabetic Wistar, used as healthy control, received monthly by intraperitoneal route, ω3 or ω6 PUFA (6.25 mg/kg) alone or plus NDGA (1.19 mg/kg) for 12 months. Diabetic rats had a worse performance in behavioural Hole-Board test. Histopathological analysis confirmed lesions in diabetic rats brain tissues. We also detected low expression of synaptophysin, a protein linked to release of neurotransmitters, by immunohistochemically techniques in eSS rats brain. Biochemical and histopathological studies of brain were performed at 12th month. Biochemical analysis showed altered parameters related to metabolism. High levels of markers of oxidative stress and inflammation were detected in plasma and brain tissues. Data were analysed by ANOVA test and paired t test was used by comparison of measurements of the same parameter at different times.

Results

The data obtained in this work showed that behavioural, biochemical and morphological alterations observed in eSS rats are compatible with previously reported indices in diabetic encephalopathy and are associated with increased glucolipotoxicity, chronic low-grade inflammation and oxidative stress burden. Experimental treatments assayed modulated the values of studied parameters.

Conclusions

The treatments tested with ω3 or ω3 plus NDGA showed improvement in the values of the studied parameters in eSS diabetic rats. These observations may form the basis to help in prevent and manage the diabetic encephalopathy.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0938-7) contains supplementary material, which is available to authorized users.

Cross-sectional correlates of oxidative stress and inflammation with glucose intolerance in prediabetes

BACKGROUND

Prediabetes is a condition in which blood glucose level is above the normal but below the diagnostic value of diabetes mellitus. Besides progression to diabetes mellitus, prediabetic subjects are at risk for cardiovascular disease (CVD). It is associated with oxidative stress and inflammation and therefore this research was conducted with the aim to evaluate the risk of cardiovascular disease in prediabetic subjects by measuring the markers of oxidative stress and inflammation and their possible correlation with glucose intolerance.

MATERIALS AND METHODS

A total of 400 human subjects were recruited for the present cross-sectional study. Of them, 200 were prediabetic subjects and 200 were age and gender-matched control subjects. Blood samples were collected from all participants and analyzed for 8-hydroxy-2'-deoxy-guanosine (8-OHdG), malondialdehyde (MDA), reduced glutathione (GSH) and high sensitivity C-reactive protein (hs-CRP).

RESULTS

The markers of oxidative stress i.e. 8-OHdG and MDA were found to be significantly increased in prediabetic subjects as compared to control subjects except GSH, which was significantly reduced in prediabetic subjects. Similarly, hs-CRP (a marker of inflammation) was significantly increased in prediabetic subjects compared to controls. On correlation analysis, 8-OHdG, MDA and hs-CRP were significantly and positively correlated with glucose intolerance in prediabetes whereas GSH showed significant negative correlation with glucose intolerance.

CONCLUSION

In conclusion, markers of oxidative stress and inflammation should be taken into consideration while evaluating the risk for CVD in prediabetes since these markers were well correlated with glucose intolerance in prediabetic subjects.

Metabolic syndrome and cancer: "The common soil hypothesis"

Metabolic syndrome (MetS) and cancer share many modifiable risk factors including age, genetic factors, obesity, physical inactivity, unhealthy diet, alcohol, smoking, endocrine disruptors exposure, circadian clock disturbances, and air pollution. MetS is closely linked to cancer, as it increases cancer risk and cancer-related mortality; moreover, cancer survivors have an increased risk of MetS. Elucidating the mechanisms linking MetS to cancer is important to prevent or delay these two conditions. Possible mechanisms explaining the relationship between MetS and cancer include hyperinsulinemia and alterations of insulin-like growth factor system, chronic subclinical inflammation, abnormalities in sex hormones metabolism and adipokines, hyperglicemia, alterations in both gene expression and hormonal profile by endocrine disruptors and air pollution, desynchronization of circadian clock. The common soil hypothesis claims that MetS may be considered a surrogate marker for dietary risk factors of cancer, and a warning sign for susceptible individuals exposed to an unhealthy diet. The common soil hypothesis and the clepsydra of foods represent a theoretical substrate to preventive intervention strategies against the pandemics of MetS and cancer: adherence to healthy dietary patterns is associated with a reduced risk of MetS, and improvement of the quality of diet is consistently associated with a reduction in cancer-related mortality.

Oxidative DNA Damage and Carotid Intima Media Thickness as Predictors of Cardiovascular Disease in Prediabetic Subjects

Prediabetes is considered as a risk factor for the development of diabetes mellitus and cardiovascular disease. The present study was conducted with the aim of finding out the relationship between oxidative DNA damage and carotid intima media thickness for the prediction of cardiovascular disease in prediabetic subjects. The study included 100 prediabetic subjects and 100 normal individuals as controls. In both cases and controls, 8-OHdG was measured by ELISA, and CIMT was measured by B mode ultrasonography. Both 8-OHdG and CIMT were significantly higher in subjects with prediabetes as compared to controls (185.80 ± 10.72 pg/mL vs. 126.13 ± 16.01 pg/mL, p < 0.001 and 0.70 ± 0.04 mm vs. 0.57 ± 0.03 mm, p < 0.001, respectively). There was significant and positive correlation of IGT with 8-OHdG (r = 0.783; p < 0.001) and CIMT (r = 0.787; p < 0.001) in prediabetic subjects. Moreover, 8-OHdG showed significant positive correlation with CIMT (r = 0.704; p < 0.001) in prediabetic subjects. In conclusion, increased 8-OHdG and CIMT in prediabetic subjects indicate that biochemical changes of atherosclerosis start even before the onset of diabetes mellitus. Hence, 8-OHdG and CIMT could be used as indicators of cardiovascular disease risk in these subjects.

Increased Micronuclei Frequency in Oral and Lingual Epithelium of Treated Diabetes Mellitus Patients

Diabetes mellitus (DM) is a metabolic disease characterized by persistent high levels of glucose in plasma. Chronic hyperglycemia is thought to increase oxidative stress and the formation of free radicals that in turn damage cells. Thus, we decided to determine the frequency of nuclear abnormalities in epithelial cells from cheek and tongue mucosa of DM patients with type 1 (DM1, treated only with insulin) and type 2 (DM2, treated with metformin) using the buccal micronucleus cytome (BMCyt) assay. Micronuclei frequency in cheek epithelial cells was higher in both DM1 (0.75 ± 0.31, P < 0.001) and DM2 (0.52 ± 0.27, P < 0.001) patients, as compared to healthy controls (0.07  ±  0.06). Similarly, micronuclei frequency in tongue epithelium was increased in DM1 (0.81  ±  0.22, P < 0.001) and DM2 (0.41  ±  0.21, P < 0.001) groups, in comparison to controls (0.06  ±  0.05). Besides, we found a positive correlation between micronuclei frequency and the onset time of DM2 in both cheek (ρ = 0.69, P < 0.001) and tongue epithelial cells (ρ = 0.71, P < 0.001), but not with onset time of DM1 or age of the patients. Considering all this, we pose that BMCyt could serve as a fast and easily accessible test to assess genotoxic damage during dental visits of DM patients, helping to monitor their disease.

The association between fasting blood glucose and the risk of primary liver cancer in Chinese males: a population-based prospective study

BACKGROUND

To investigate the association between fasting blood glucose (FBG) levels and the risk of incident primary liver cancer (PLC) in Chinese males, a large prospective cohort was performed in the current study.

METHODS

A total of 109 169 males participating in the routine checkups every two years were recruited in the Kailuan male cohort study since May 2006. Cox proportional hazards regression models and restricted cubic spline (RCS) were used to evaluate the association between levels of baseline FBG and the risk of incident PLC.

RESULTS

Compared to the males with normal FBG (3.9⩽FBG<6.1 mmol l^-1), the males with impaired fasting glucose (IFG: 6.1⩽FBG<7.0 mmol l^-1) and diabetes mellitus (DM: FBG ⩾7.0 mmol l^-1) had a 60% (95% CI: 1.09-2.35) and a 58% (95% CI: 1.07-2.34) higher risk of incident PLC, respectively. Subgroup analysis found that IFG increased the risk of PLC among the non-smoker (HR=1.73, 95% CI: 1.01-2.98) and current alcohol drinker (HR=1.80, 95% CI: 1.03-3.16). While DM increased the risk of PLC especially among the males with normal BMI (<25 kg m^-2) (HR=1.76, 95% CI: 1.05-2.94) and the HBV negativity (HR=1.89, 95% CI: 1.16-3.09), RCS analysis showed a positive non-linearly association between the FBG levels and the risk of PLC (p-overall=0.041, p-non-linear=0.049).

CONCLUSIONS

Increased FBG may be an important and potentially modifiable exposure that could have key scientific and clinical importance for preventing PLC development.

Insights into the relationships between diabetes, prediabetes, and cancer

Diabetes mellitus and cancer are two growing health problems. They have in common many modifiable risk factors including sex, age, obesity, physical activity, diet, alcohol, and smoking, and have a long latency before overtly manifesting. Patients with diabetes experience a roughly 20-25% higher cancer incidence compared to individuals without diabetes, and it depends on cancer site. Moreover, patients with diabetes who further develop cancer have increased early and late mortality in comparison with cancer patients without diabetes. Prediabetes and metabolic syndrome are also related to an increased risk of developing and die from cancer. Possible mechanisms linking diabetes and prediabetes with cancer include hyperglycemia (endogenous or exogenous), hyperinsulinemia, and alterations of insulin-like growth factor system, chronic subclinical inflammation, abnormalities in sex hormone metabolism, and adipokines. It becomes crucial to define the right orientation of the associations between diabetes and cancer in order to identify the modifiable pathogenic mechanisms. The common soil hypothesis claims that prediabetes and diabetes, as well as metabolic syndrome, may be considered a surrogate sign for dietary risk factors of cancer. The clepsydra of foods may help choose foods associated with healthy benefit while avoiding foods associated with harm, including cancer.

Vitamin C decreases the obesogenic and hyperglycemic effect of invert sugar in prediabetic rats

ABSTRACT Objective: To evaluate whether vitamin C can help to prevent obesity and hyperglycemia in Wistar rats treated with excess invert sugar to induce prediabetes. Methods: One hundred-day-old Male Wistar rats with a mean weight of 336.58±23.43g were randomly assigned to the following groups: (1) control, receiving water (C); (2) invert sugar control, receiving a 32% watery solution of invert sugar; (3) vitamin C control, receiving a watery solution of vitamin C (60mg/L), and (4) vitamin C plus invert sugar, receiving a watery solution of vitamin C and invert sugar. All animals had access to chow and water ad libitum and were treated for 17 weeks. Prediabetes was assessed according to two criteria: obesity (based on body mass indexand peritoneal fat content) and impaired glucose tolerance (assessed by the intraperitoneal glucose tolerance test and expressed as area under the curve) . Results: Group invert sugar control gained significantly more weight (p=0.035) and visceral fat (p<0.001) than groups vitamin C control and vitamin C plus invert sugar. Consequently, groups vitamin C control and vitamin C plus invert sugar had gained as little body mass index as group C by the end of the experiment. Vitamin C decreased the fasting glycemia of both groups supplemented with vitamin C and normalized the glucose tolerance of group vitamin C plus invert sugar, whose area under the curve matched that of group C. Conclusion: Vitamin C has anti-obesogenic and glycemia-lowering effects in Wistar rats, which might be promising to prediabetics. Future studies are needed to understand the anti-obesogenic and anti-hyperglycemic mechanisms of vitamin C in prediabetes.

Elevated urinary levels of 8-oxo-2'-deoxyguanosine, (5'R)- and (5'S)-8,5'-cyclo-2'-deoxyadenosines, and 8-iso-prostaglandin F2α as potential biomarkers of oxidative stress in patients with prediabetes

Prediabetes is the preclinical stage of type 2 diabetes mellitus (T2DM) with intermediate state of hyperglycemia. Hyperglycemia results in a state of oxidative stress, which may contribute to the production of insulin resistance, β-cell dysfunction and long-term complications of diabetes. Novel approaches are required for prevention and treatment of diabetes. New biomarkers that can be used in risk stratification and therapy control as supplementary to current parameters are needed. These biomarkers may facilitate a more individualized and sufficient treatment of diabetes. Therefore, the aim of this study was to investigate the levels of oxidatively induced DNA damage products, 8-oxo-2'-deoxyguanosine (8-oxo-dG) (also known as 8-OH-dG), (5'R)- and (5'S)-8,5'-cyclo-2'-deoxyadenosines (R-cdA and S-cdA), and the lipid peroxidation product 8-iso-prostaglandin F2α (8-iso-PGF2α) as reliable oxidative stress markers in patients with prediabetes or T2DM in comparison with healthy volunteers. Urine samples were collected from these subjects. Absolute quantification of 8-oxo-dG, R-cdA, S-cdA and 8-iso-PGF2α was achieved by liquid chromatography-isotope dilution tandem mass spectrometry. The levels of 8-oxo-dG, S-cdA and 8-iso-PGF2α were significantly greater in prediabetes patients than those in healthy volunteers. T2DM patients also had higher levels of 8-oxo-dG than healthy volunteers. No statistically significant difference was observed for R-cdA levels. 8-Oxo-dG levels positively correlated with R-cdA and S-cdA levels for prediabetes and newly diagnosed T2DM. S-cdA levels and HbA1c were found negatively correlated in prediabetes patients. Also 8-iso-PGF2α levels and HbA1c were found negatively correlated in prediabetes patients. These results indicate that oxidatively induced macromolecular damage appears before the establishment of T2DM. Thus, our data suggest that oxidatively induced DNA damage and lipid peroxidation products that were found to be elevated in prediabetic stage may be used as early disease markers in patients at risk for T2DM.

Evaluation of DNA damage in Type 2 diabetes mellitus patients with and without peripheral neuropathy: A study in South Indian population

Background:

The increasing incidence of Type 2 diabetes mellitus globally has collaterally increased the incidence of diabetes-associated complications such as neuropathy. Oxidative stress induced DNA damage is one of the mechanisms implicated in the pathogenesis of diabetic complications. Here we aimed to evaluate the extent of DNA damage in diabetes patients with and without clinical neuropathy using the Cytokinesis Block Micronucleus Cytome assay, in a group of South Indian population.

Materials and Methods:

The Cytokinesis Block Micronucleus Cytome assay was performed in lymphocyte cultures of 42 type 2 diabetes patients (22 with neuropathy and 20 without neuropathy) and 42 age and sex matched controls. Nuclear aberrations like Nuclear Buds, Nucleoplasmic Bridges and Micronuclei were analyzed.

Results:

The frequency of nuclear aberrations in diabetes patients with neuropathy was higher than compared to diabetes patients without neuropathy. The mean frequencies of nuclear aberrations per cell in diabetes patients with neuropathy and without neuropathy were 0.02 ± 0.02 and 0.01 ± 0.01, respectively. This was significantly higher than in the controls (0.002 ± 0.002) (P < 0.0001). An increasing trend of nuclear aberrations in correlation with the duration of diabetes was observed.

Conclusion:

This study highlights the use of the Cytokinesis Block Micronucleus Cytome assay as a potent tool for the identification of DNA damage, which may prove to be useful biomarker to assess the severity diabetes-associated complications such as neuropathy. Implementation of this technique at the clinical level would potentially enhance the quality of management of patients with diabetes and its complications like neuropathy.

Prediabetes and the risk of cancer: a meta-analysis

AIMS/HYPOTHESIS

The results from prospective cohort studies of prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and risk of cancer are controversial. We conducted a meta-analysis to evaluate the risk of cancer in association with impaired fasting glucose and impaired glucose tolerance.

METHODS

The PubMed, EMBASE and Cochrane Library databases were searched for prospective cohort studies with data on prediabetes and cancer. Two independent reviewers assessed the reports and extracted the data. Prospective studies were included if they reported adjusted RRs with 95% CIs for the association between cancer and prediabetes. Subgroup analyses were conducted according to endpoint, age, sex, ethnicity, duration of follow-up and study characteristics.

RESULTS

Data from 891,426 participants were derived from 16 prospective cohort studies. Prediabetes was associated with an increased risk of cancer overall (RR 1.15; 95% CI 1.06, 1.23). The results were consistent across cancer endpoint, age, duration of follow-up and ethnicity. There was no significant difference for the risk of cancer with different definitions of prediabetes. In a site-specific cancer analysis, prediabetes was significantly associated with increased risks of cancer of the stomach/colorectum, liver, pancreas, breast and endometrium (all p < 0.05), but not associated with cancer of the bronchus/lung, prostate, ovary, kidney or bladder. The risks of site-specific cancer were significantly different (p = 0.01) and were highest for liver, endometrial and stomach/colorectal cancer.

CONCLUSIONS/INTERPRETATION

Overall, prediabetes was associated with an increased risk of cancer, especially liver, endometrial and stomach/colorectal cancer.

Vitamin C intake reduces the cytotoxicity associated with hyperglycemia in prediabetes and type 2 diabetes

Hyperglycemia leads to the formation of free radicals and advanced glycation end-products (AGEs). Antioxidants can reduce the level of protein glycation and DNA damage. In this study, we compared the levels of vitamin C intake, which is among the most abundant antioxidants obtained from diet, with the levels of fasting plasma glucose (FPG), glycated hemoglobin (A1C), DNA damage, and cytotoxicity in prediabetic subjects and type 2 diabetic subjects. Our results indicated that there was no significant correlation between FPG or A1C and DNA damage parameters (micronuclei, nucleoplasmic bridges, and nuclear buds). FPG and A1C correlated with necrosis (r = 0.294; P = 0.013 and r = 0.401; P = 0.001, resp.). Vitamin C intake correlated negatively with necrosis and apoptosis (r = −0.246; P = 0.040, and r = −0.276; P = 0.021, resp.). The lack of a correlation between the FPG and A1C and DNA damage could be explained, at least in part, by the elimination of cells with DNA damage by either necrosis or apoptosis (cytotoxicity). Vitamin C appeared to improve cell survival by reducing cytotoxicity. Therefore, the present results indicate the need for clinical studies to evaluate the effect of low-dose vitamin C supplementation in type 2 diabetes.