Changes in the erythrocyte glutathione concentration in the course of diabetes mellitus

Detection of GSH with a dual-mode biosensor based on carbon quantum dots prepared from dragon fruit peel and the T-Hg(II)-T mismatch

Glutathione (GSH) is commonly used as a diagnostic biomarker for many diseases. In this study, based on carbon quantum dots prepared from dragon fruit peel (D-CQDs) and the T-Hg(II)-T mismatch, a dual-mode biosensor was developed for the detection of GSH. This system consists of two single-stranded DNA (ssDNA). DNA1 was the T-rich sequence; DNA2 was attached to streptavidin-coated magnetic beads and consisted of T-rich and G-rich fragments. Due to the presence of Hg(II), the T-Hg(II)-T mismatch was formed between T-rich fragments of two ssDNA. In the presence of GSH, Hg(II) detached from dsDNA and bound with GSH to form a new complex. The G-rich fragment assembled with the hemin shed from D-CQDs to form the G-quadruplex/hemin complex. At this time, in fluorescence mode, the fluorescence of D-CQDs quenched by hemin could be restored. In colorimetric mode, after the magnetic beads separate, a visual signal could be produced by catalyzing the oxidation of ABTS using the peroxide-like activity of the G-quadruplex/hemin complex. This biosensor in both fluorescence mode and colorimetric mode had excellent selectivity and sensitivity, and the limit of detection was 0.089 µM and 0.26 µM for GSH, respectively. Moreover, the proposed dual-mode biosensor had good application prospects for detection of GSH.

Blood Viscosity Changes in Diabetes Mellitus: A 20-Year Bibliometric Review and Future Directions

Changes in hematological parameters due to diabetes are reflected in changes in whole blood viscosity (WBV). Understanding the impact of diabetes and its cardiovascular disease (CVD) complications can provide substantiation of how laboratory tests for WBV are useful to monitor the progression and treatment. The review examines research work done in the past 20 years to provide a framework for the present agenda. This was a narrative review that followed the standard Scale for the Assessment of Narrative Review Articles (SANRA) approach. It includes both conceptual and empirical reviews. WBV was appraised in the context of bibliographic research on diabetes and other related factors such as metabolic syndrome (MetS) and oxidative stress. The association of abnormal erythrocytes as well as the relationship between WBV and MetS is established. Changes in diabetes that contribute to the development of diabetic cardiovascular complications occur through the pathway of WBV physiology. However, longitudinal analysis is very limited. There is a dearth of longitudinal study data on WBV in diabetes management. This lack of data justifies a need for further studies, especially prospective and retrospective analysis, to investigate the prevalence of diabetes mellitus about the prevalence of cardiovascular complications indices, especially estimated WBV (eWBV) between periods and within cohorts.

Exploratory risk prediction of type II diabetes with isolation forests and novel biomarkers

Type II diabetes mellitus (T2DM) is a rising global health burden due to its rapidly increasing prevalence worldwide, and can result in serious complications. Therefore, it is of utmost importance to identify individuals at risk as early as possible to avoid long-term T2DM complications. In this study, we developed an interpretable machine learning model leveraging baseline levels of biomarkers of oxidative stress (OS), inflammation, and mitochondrial dysfunction (MD) for identifying individuals at risk of developing T2DM. In particular, Isolation Forest (iForest) was applied as an anomaly detection algorithm to address class imbalance. iForest was trained on the control group data to detect cases of high risk for T2DM development as outliers. Two iForest models were trained and evaluated through ten-fold cross-validation, the first on traditional biomarkers (BMI, blood glucose levels (BGL) and triglycerides) alone and the second including the additional aforementioned biomarkers. The second model outperformed the first across all evaluation metrics, particularly for F1 score and recall, which were increased from 0.61 ± 0.05 to 0.81 ± 0.05 and 0.57 ± 0.06 to 0.81 ± 0.08, respectively. The feature importance scores identified a novel combination of biomarkers, including interleukin-10 (IL-10), 8-isoprostane, humanin (HN), and oxidized glutathione (GSSG), which were revealed to be more influential than the traditional biomarkers in the outcome prediction. These results reveal a promising method for simultaneously predicting and understanding the risk of T2DM development and suggest possible pharmacological intervention to address inflammation and OS early in disease progression.

Oxidative Stress in Prediabetic Young Adults

Background Malondialdehyde (MDA) and nitric oxide (NO) are considered specific biomarkers for oxidative stress. Oxidative stress in prediabetics with an augmented potential for the onset of diabetes is at least partly responsible for the various complications of diabetes. Evidence shows that the early features of cell injury are due to transient acute elevations in blood glucose. This study aims to determine whether oxidative stress in prediabetic young adults increases the risk of developing diabetes. Aim and objectives We envisaged a study to determine whether the parameters representing oxidative stress are deranged in prediabetics. Materials and methods The study was conducted on prediabetic young individuals from 18 to 35 years, screened from the tertiary-level hospital, and a similar group of non-prediabetic young individuals identified from the same in a tertiary-level hospital in India. Results We observed significant elevations in prediabetics in the following oxidative stress parameters: MDA (P= <0.001), and NO (P= <0.001); indicating that these parameters were significantly higher among the prediabetics than the controls. We also observed significantly greater body weight, waist circumference, and BMI among the prediabetics than the controls. Conclusion Early identification and appropriate treatment of hyperglycemia in prediabetics is essential, as impairments in pancreatic beta-cell functioning and resistance to insulin are already present before the onset of type 2 diabetes mellitus (T2DM). Owing to the high potential for mortality and morbidity due to cardiovascular diseases (CVDs) as a complication of diabetes, treatment plans must be put in place early enough so that complications can be prevented. Inflammation and oxidative stress may be viewed as valuable targets to hinder the evolution of T2DM from prediabetes.

Comparative Analysis of Biomarkers in Type 2 Diabetes Patients With and Without Comorbidities: Insights Into the Role of Hypertension and Cardiovascular Disease

Background

Type 2 diabetes mellitus (T2DM) are 90% of diabetes cases, and its prevalence and incidence, including comorbidities, are rising worldwide. Clinically, diabetes and associated comorbidities are identified by biochemical and physical characteristics including glycemia, glycated hemoglobin (HbA1c), and tests for cardiovascular, eye and kidney disease.

Objectives

Diabetes may have a common etiology based on inflammation and oxidative stress that may provide additional information about disease progression and treatment options. Thus, identifying high-risk individuals can delay or prevent diabetes and its complications.

Design

In patients with or without hypertension and cardiovascular disease, as part of progression from no diabetes to T2DM, this research studied the changes in biomarkers between control and prediabetes, prediabetes to T2DM, and control to T2DM, and classified patients based on first-attendance data. Control patients and patients with hypertension, cardiovascular, and with both hypertension and cardiovascular diseases are 156, 148, 61, and 216, respectively.

Methods

Linear discriminant analysis is used for classification method and feature importance, This study examined the relationship between Humanin and mitochondrial protein (MOTSc), mitochondrial peptides associated with oxidative stress, diabetes progression, and associated complications.

Results

MOTSc, reduced glutathione and glutathione disulfide ratio (GSH/GSSG), interleukin-1β (IL-1β), and 8-isoprostane were significant (P < .05) for the transition from prediabetes to t2dm, highlighting importance of mitochondrial involvement. complement component 5a (c5a) is a biomarker associated with disease progression and comorbidities, gsh gssg, monocyte chemoattractant protein-1 (mcp-1), 8-isoprostane being most important biomarkers.

Conclusions

Comorbidities affect the hypothesized biomarkers as diabetes progresses. Mitochondrial oxidative stress indicators, coagulation, and inflammatory markers help assess diabetes disease development and provide appropriate medications. Future studies will examine longitudinal biomarker evolution.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Hypoglycemic Efficacy of Rh-aFGF Variants in Treatment of Diabetes in ZDF Rats

Acidic fibroblast growth factor (aFGF) is a promising regulator of glucose with no adverse effects of hypoglycemia. Previous researches revealed that aFGF mediated adipose tissue remodeling and insulin sensitivity. These findings supported rh-aFGF₁₃₅ would be used as a new candidate for the treatment of insulin resistance and type 2 diabetes. In this study, we aimed to investigate the hypoglycemic efficacy of recombinant human acidic fibroblast growth factor 135 (rh-aFGF₁₃₅) with low mitogenic in type 2 diabetic ZDF rats. ZDF rats were treated with rh-aFGF₁₃₅ at a daily dosage of 0.25 and 0.50 mg/kg by tail intravenous injection for 5 weeks. The blood glucose levels, oral glucose tolerance test, insulin tolerance test, HOMA-IR for insulin resistance, serum biochemical parameters, and the histopathological changes of adipose tissue, liver and other organs were detected at designed time point. The glucose uptake activity and anti-insulin resistance effect of rh-aFGF₁₃₅ were also detected in HepG2 cells. Results revealed that rh-aFGF₁₃₅ exhibited a better hypoglycemic effect compared with vehicle group and without the adverse effect of hypoglycemia in ZDF rats. Compared with vehicle group, rh-aFGF₁₃₅ significantly improved the situation of hyperglycemia and insulin resistance. Rh-aFGF₁₃₅ decreased ALT, AST, GSP, and FFA levels noticeably compared with vehicle control group (P < 0.01 or P < 0.001). After 5 weeks of treatment, high-dosage rh-aFGF₁₃₅ could remodel adipose tissue, and has no influence on other organs. H&E staining showed that rh-aFGF₁₃₅ reduced the size of adipocytes. In addition, rh-aFGF₁₃₅ may improve insulin resistance partly by increasing the protein expression of p-IRS-1 (human Ser 307). As a hypoglycemic drug for long-term treatment, rh-aFGF₁₃₅ would be a potentially safe candidate for the therapy of type 2 diabetes.

Toxicokinetics of methylmercury in diabetic KK-Ay mice and C57BL/6 mice

We compared the toxicokinetics of methylmercury (MeHg) in KK-Ay type 2 diabetic mice and C57BL/6J mice to evaluate how metabolic changes associated with diabetes affect MeHg toxicokinetics. A single dose of MeHg (0.2, 1, or 5 mg mercury/kg) was administered orally to 12-week-old KK-Ay and C57BL/6J male mice. Total mercury concentrations in plasma, blood cells, whole blood, and tissues (brain, kidneys, liver, and pancreas) were measured after 4, 7, 11, and 14 days. The volume of distribution/bioavailability and the elimination rate constant per day were higher in KK-Ay mice, while the terminal elimination half-life was lower in almost all samples of KK-Ay mice. The area under the curve was lower in all blood and almost all tissue samples from KK-Ay mice. Total clearance/bioavailability was lower in all blood and tissue samples of KK-Ay mice at all MeHg doses. These results indicate that MeHg is more rapidly absorbed by, and eliminated from, the blood cells, brain, liver, kidney, and pancreas of KK-Ay mice under the experimental conditions. Different patterns of tissue-to-plasma and tissue-to-whole blood partition coefficients suggest that notable differences in MeHg transfer between plasma and blood cells affect its distribution in tissues of the two mouse strains. These findings are useful to understand the selective distribution of MeHg to target organs and the sensitivity to MeHg in pathological states.

Sulforaphane: Its "Coming of Age" as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease

A growing awareness of the mechanisms by which phytochemicals can influence upstream endogenous cellular defence processes has led to intensified research into their potential relevance in the prevention and treatment of disease. Pharmaceutical medicine has historically looked to plants as sources of the starting materials for drug development; however, the focus of nutraceutical medicine is to retain the plant bioactive in as close to its native state as possible. As a consequence, the potency of a nutraceutical concentrate or an extract may be lower than required for significant gene expression. The molecular structure of bioactive phytochemicals to a large extent determines the molecule's bioavailability. Polyphenols are abundant in dietary phytochemicals, and extensive in vitro research has established many of the signalling mechanisms involved in favourably modulating human biochemical pathways. Such pathways are associated with core processes such as redox modulation and immune modulation for infection control and for downregulating the synthesis of inflammatory cytokines. Although the relationship between oxidative stress and chronic disease continues to be affirmed, direct-acting antioxidants such as vitamins A, C, and E, beta-carotene, and others have not yielded the expected preventive or therapeutic responses, even though several large meta-analyses have sought to evaluate the potential benefit of such supplements. Because polyphenols exhibit poor bioavailability, few of their impressive in vitro findings have been replicated in vivo. SFN, an aliphatic isothiocyanate, emerges as a phytochemical with comparatively high bioavailability. A number of clinical trials have demonstrated its ability to produce favourable outcomes in conditions for which there are few satisfactory pharmaceutical solutions, foreshadowing the potential for SFN as a clinically relevant nutraceutical. Although myrosinase-inert broccoli sprout extracts are widely available, there now exist myrosinase-active broccoli sprout supplements that yield sufficient SFN to match the doses used in clinical trials.

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.

Vitamin E Deficiency and Oxidative Status are Associated with Prediabetes in Apparently Healthy Subjects

BACKGROUND

Previous studies have indicated that vitamin E deficiency and oxidative stress affect the beta cell function. Hence, the aim of this study was to determine the association between vitamin E deficiency and oxidative status with prediabetes in apparently healthy subjects.

METHODS

Apparently healthy men and women aged 18-65 years were enrolled in a case-control study. Individuals with new diagnosis of prediabetes were considered as cases and compared with a control group of individuals with normal glucose tolerance. Smoking, alcohol intake, pregnancy, diabetes, kidney disease, liver disease, cardiovascular disease, malignancy, glucocorticoid treatment and consumption of lipid-lowering drugs, antioxidants and vitamin supplements were exclusion criteria. Vitamin E deficiency was defined by serum levels of α-tocopherol <11.6 μmol/L, oxidative status was assessed by total antioxidant capacity and lipid peroxidation, and prediabetes was considered by the presence of impaired fasting glucose and/or impaired glucose tolerance.

RESULTS

A total of 148 subjects were allocated into the case (n = 74) and control (n = 74) groups. The frequency of vitamin E deficiency was higher in the case group (41.8%) compared with the control group (35.1%), p = 0.03. The logistic regression analysis adjusted by age, waist circumference and body mass index, revealed a significant association between vitamin E deficiency (OR 3.23; 95% CI: 1.34-7.79, p = 0.009), lipoperoxidation (OR 2.82; CI 95%: 1.42-5.59, p = 0.003) and total antioxidant capacity (OR 0.93; CI 95%: 0.90-0.96, p <0.001) with prediabetes.

CONCLUSIONS

Results of the present study suggest that both vitamin E deficiency and oxidative status are associated with prediabetes in apparently healthy subjects.

Increase in serum albumin concentration is associated with prediabetes development and progression to overt diabetes independently of metabolic syndrome

Aim

Serum albumin concentration is associated with both type 2 diabetes and metabolic syndrome (MetS). We sought to investigate whether baseline serum albumin and change in serum albumin could be independent risk factors for prediabetes in subjects without MetS. We further examined the effect of serum albumin on progression to overt diabetes in subjects who developed prediabetes.

Methods

Among 10,792 participants without diabetes and MetS who consecutively underwent yearly health check-ups over six years, 9,807 subjects without incident MetS were enrolled in this longitudinal retrospective study. The risk of developing prediabetes (impared fasting glucose or hemoglobin A1c) was analyzed according to baseline and percent change in serum albumin concentration using Cox regression analysis. Serial changes in serum albumin concentration were measured from baseline to one year before prediabetes diagnosis, and then from the time of prediabetes diagnosis to progression to overt diabetes or final follow-up.

Results

A total of 4,398 incident cases of prediabetes developed during 35,807 person-years (median 3.8 years). The hazard ratio for incident prediabetes decreased as percent change in serum albumin concentration (quartiles and per 1%) increased in a crude and fully adjusted model. However, baseline serum albumin concentration itself was not associated with prediabetic risk. Serum albumin levels kept increasing until the end of follow-up in prediabetic subjects who returned to normal glycemic status, whereas these measures did not change in prediabetic subjects who developed type 2 diabetes. Serum albumin concentration measured at the end of follow-up was the highest in the regression group, compared to the stationary (p = 0.014) or progression groups (p = 0.009).

Conclusions

Increase in serum albumin concentration might protect against early glycemic deterioration and progression to type 2 diabetes even in subjects without MetS.

Glutamate Cysteine Ligase-Modulatory Subunit Knockout Mouse Shows Normal Insulin Sensitivity but Reduced Liver Glycogen Storage

Glutathione (GSH) deficits have been observed in several mental or degenerative illness, and so has the metabolic syndrome. The impact of a decreased glucose metabolism on the GSH system is well-known, but the effect of decreased GSH levels on the energy metabolism is unclear. The aim of the present study was to investigate the sensitivity to insulin in the mouse knockout (KO) for the modulatory subunit of the glutamate cysteine ligase (GCLM), the rate-limiting enzyme of GSH synthesis. Compared to wildtype (WT) mice, GCLM-KO mice presented with reduced basal plasma glucose and insulin levels. During an insulin tolerance test, GCLM-KO mice showed a normal fall in glycemia, indicating normal insulin secretion. However, during the recovery phase, plasma glucose levels remained lower for longer in KO mice despite normal plasma glucagon levels. This is consistent with a normal counterregulatory hormonal response but impaired mobilization of glucose from endogenous stores. Following a resident-intruder stress, during which stress hormones mobilize glucose from hepatic glycogen stores, KO mice showed a lower hyperglycemic level despite higher plasma cortisol levels when compared to WT mice. The lower hepatic glycogen levels observed in GCLM-KO mice could explain the impaired glycogen mobilization following induced hypoglycemia. Altogether, our results indicate that reduced liver glycogen availability, as observed in GCLM-KO mice, could be at the origin of their lower basal and challenged glycemia. Further studies will be necessary to understand how a GSH deficit, typically observed in GCLM-KO mice, leads to a deficit in liver glycogen storage.

Endothelial Dysfunction in Type 2 Diabetes Mellitus

Endothelial dysfunction is an imbalance in the production of vasodilator factors and when this balance is disrupted, it predisposes the vasculature towards pro-thrombotic and pro-atherogenic effects. This results in vasoconstriction, leukocyte adherence, platelet activation, mitogenesis, pro-oxidation, impaired coagulation and nitric oxide production, vascular inflammation, atherosclerosis and thrombosis. Endothelial dysfunction is focussed as it is a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. Under physiological conditions, there is a balanced release of endothelial-derived relaxing and contracting factors, but this delicate balance is altered in diabetes mellitus and atherosclerosis, thereby contributing to further progression of vascular and end-organ damage. This review focuses on endothelial dysfunction in atherosclerosis, insulin resistance, metabolic syndrome, oxidative stress associated with diabetes mellitus, markers and genetics that are implicated in endothelial dysfunction.

Highly sensitive determination of reduced glutathione based on a cobalt nanoparticle implanted-modified indium tin oxide electrode

Cobalt nanoparticle modified indium tin oxide (CoNP/ITO) electrodes fabricated by ion implantation were applied for the detection of reduced glutathione (GSH).

Oxidative stress and triglycerides as predictors of subclinical atherosclerosis in prediabetes

BACKGROUND

The role of triglycerides in early preclinical atherosclerosis is controversial. Antioxidant markers may be associated with triglyceride levels in early preclinical atherosclerosis especially when fasting plasma glucose is raised.

METHODS

This cross-sectional study included 127 participants attending the Diabetes Screening Clinic, Charles Sturt University, Australia.

RESULTS

Serum 8-hydroxy-2-deoxy-guanosine (8-OHdG) was significantly greater in the impaired fasting glucose (IFG) group compared with the control group (536.7 pg/ml ± 249.8 versus 171.4 pg/ml ± 96.9, respectively). The increase in 8-OHdG was associated with a mildly non-significant elevation in low-density lipoprotein level (3.2 ± 1.1 mmol/l) and a poor level of high-density lipoprotein (1.31 ± 0.3 mmol/l) in the IFG group. However, a significant increase in triglycerides (1.6 ± 0.97 mmol/l; P < 0.05) in the IFG group was observed. Erythrocyte reduced glutathione (GSH) levels in the IFG group, although increased, were also not significantly different to control.

CONCLUSION

A significant increase in 8-OHdG is associated with increased levels of triglycerides in the absence of significant changes in reduced GSH and normal levels of cholesterol in the IFG cohort, suggesting that oxidative stress may be present and indicative of subclinical atherosclerosis.

[L-cysteine influx in diabetic erythrocytes]

Erythrocyte oxidative stress has been implicated in the pathogenesis of diabetes mellitus, and the deficiency of antioxidant defense by the glutathione (GSH) pathway is thought to be one of the factors responsible for development of complications in diabetes. Erythrocytes require L-cysteine for thesynthesis of GSH and the rate of synthesis is determined only by L-cysteine availability. In the present study we have found that the L-cysteine influx in erythrocytes from type 2 diabetic patients was significantly lower compared to age-matched controls. The decreased influx may be one of the factors leading to low GSH concentration observed in type 2 diabetes. Since L-cysteine is the limiting amino acid in GSH synthesis, any strategy aimed to increase L-cysteine influx in erythrocytes may be beneficial for type 2 diabetic patients.

8-Hydroxy-2-deoxy-guanosine identifies oxidative DNA damage in a rural prediabetes cohort

BACKGROUND

Rising levels of oxidative stress play an important role in the pathogenesis of type 2 diabetes mellitus. Therefore, we investigated the serum level of 8-hydroxy-2-deoxy-guanosine (8-OHdG) as an early oxidative stress marker in patients with prediabetes and with type 2 diabetes mellitus.

SUBJECTS AND METHODS

Convenience sampling from people attending a diabetes screening clinic. Participants at the rural diabetes screening clinic had their medical history recorded as well as body mass index, blood glucose, cholesterol, glutathione, malondialdehyde, fasting blood glucose and 8-OHdG measured. Statistical analysis was performed using ANOVA followed by Sheffe posthoc test for between-group differences.

RESULTS

The 8-OHdG level was significantly greater in the prediabetes (516.5 +/- 260 pg/ml) compared to control group (177.8 +/- 91 pg/ml; P < 0.01). The diabetes group (1926.9 +/- 1197 pg/ml) had the highest level of 8-OHdG, being approximately four times greater compared to the prediabetes group (P < 0.001). No significant change in the cholesterol profile, MDA level indicative of lipid peroxidation and antioxidant activity as measured by erythrocyte reduced glutathione was observed in the prediabetes group compared to the control group (P > 0.05).

CONCLUSIONS

8-OHdG levels in both the prediabetes and diabetes group were increased from control values suggesting a role for 8-OHdG as an early disease marker that may be more sensitive compared to cholesterol, MDA and erythrocyte reduced glutathione levels, which were within normal limits. This is of clinical significance as 8-OHdG is a strong indicator of oxidative stress related DNA damage within blood vessel walls and other tissue that increases the risk of cardiovascular disease.

Positive and negative regulation of insulin signaling by reactive oxygen and nitrogen species

Regulated production of reactive oxygen species (ROS)/reactive nitrogen species (RNS) adequately balanced by antioxidant systems is a prerequisite for the participation of these active substances in physiological processes, including insulin action. Yet, increasing evidence implicates ROS and RNS as negative regulators of insulin signaling, rendering them putative mediators in the development of insulin resistance, a common endocrine abnormality that accompanies obesity and is a risk factor of type 2 diabetes. This review deals with this dual, seemingly contradictory, function of ROS and RNS in regulating insulin action: the major processes for ROS and RNS generation and detoxification are presented, and a critical review of the evidence that they participate in the positive and negative regulation of insulin action is provided. The cellular and molecular mechanisms by which ROS and RNS are thought to participate in normal insulin action and in the induction of insulin resistance are then described. Finally, we explore the potential usefulness and the challenges in modulating the oxidant-antioxidant balance as a potentially promising, but currently disappointing, means of improving insulin action in insulin resistance-associated conditions, leading causes of human morbidity and mortality of our era.

Gamma-Glutamyltransferase Activity and Total Antioxidant Status in Serum and Platelets of Patients with Community-acquired Pneumonia

BACKGROUND

We undertook this study to analyze serum and platelet gamma-glutamyltransferase (GGT) activity and total antioxidant status (TAS) concentration during the course of pneumonia and to compare them between patients with normal platelet count and those who developed reactive thrombocytosis.

METHODS

Platelet count, GGT activity and TAS concentration in serum (S) and platelet (Plt) isolates were measured in 60 patients with community-acquired pneumonia (CAP) on admission and at discharge.

RESULTS

At the end of treatment, platelet count increased significantly from the value recorded on admission. By the end of treatment, 42% of patients developed reactive thrombocytosis. Serum and platelet GGT activity was higher, whereas (S)TAS was significantly lower in CAP patients than in control subjects. On admission, (Plt)TAS was significantly higher in CAP patients as compared with control subjects; at discharge, (Plt)TAS was lower in comparison with either patient admission and control subjects. GGT activity and TAS concentration in serum and platelet isolate on admission did not differ significantly between patients with and without thrombocytosis. At discharge, (S)GGT activity showed no significant changes, whereas (Plt)GGT decreased significantly in patients with thrombocytosis as compared with those without thrombocytosis. In patients with thrombocytosis, (S)TAS concentration showed no significant difference, whereas (Plt)TAS concentration measured at discharge was significantly lower in patients with thrombocytosis as compared to those with normal platelet count.

CONCLUSIONS

The pattern of changes in (Plt)GGT catalytic activity and TAS concentration might be indicative of a certain role of thrombocytosis during treatment in patients with CAP. Further investigations are necessary to clarify these changes.