Oxidative DNA damage and augmentation of poly(ADP-ribose) polymerase/nuclear factor-kappa B signaling in patients with Type 2 diabetes and microangiopathy

Human umbilical cord mesenchymal stem cells attenuate diabetic nephropathy through the IGF1R-CHK2-p53 signalling axis in male rats with type 2 diabetes mellitus

Diabetes mellitus (DM) is a disease syndrome characterized by chronic hyperglycaemia. A long-term high-glucose environment leads to reactive oxygen species (ROS) production and nuclear DNA damage. Human umbilical cord mesenchymal stem cell (HUcMSC) infusion induces significant antidiabetic effects in type 2 diabetes mellitus (T2DM) rats. Insulin-like growth factor 1 (IGF1) receptor (IGF1R) is important in promoting glucose metabolism in diabetes; however, the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear. In this study, a DM rat model was induced with high-fat diet feeding and streptozotocin (STZ) administration and rats were infused four times with HUcMSC. Blood glucose, interleukin-6 (IL-6), IL-10, glomerular basement membrane, and renal function were examined. Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays. The expression of IGF1R, phosphorylated checkpoint kinase 2 (p-CHK2), and phosphorylated protein 53 (p-p53) was examined using immunohistochemistry (IHC) and western blot analysis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of 8-hydroxydeoxyguanosine (8-OHdG). Flow cytometry experiments were used to detect the surface markers of HUcMSC. The identification of the morphology and phenotype of HUcMSC was performed by way of oil red "O" staining and Alizarin red staining. DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane, increased the expression of IGF1 and IGF1R. IGF1R interacted with CHK2, and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells. When cisplatin was used to induce DNA damage, the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment. HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats. The expression of IGF1, IGF1R, p-CHK2, and p-p53, and the level of 8-OHdG in the DM group increased significantly compared with those in the control group, and decreased after HUcMSC treatment. Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage. HUcMSC infusion protected against kidney injury in DM rats. The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.

PAR level mediates the link between ROS and inflammatory response in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is characterized by disrupted glucose homeostasis and metabolic abnormalities, with oxidative stress and inflammation playing pivotal roles in its pathophysiology. Poly(ADP-ribosyl)ation (PARylation) is a post-translational process involving the addition of ADP-ribose polymers (PAR) to target proteins. While preclinical studies have implicated PARylation in the interplay between oxidative stress and inflammation in T2DM, direct clinical evidence in humans remains limited. This study investigates the relationship between oxidative stress, PARylation, and inflammatory response in T2DM patients.

METHODS

This cross-sectional investigation involved 61 T2DM patients and 48 controls. PAR levels were determined in peripheral blood cells (PBMC) by ELISA-based methodologies. Oxidative stress was assessed in plasma and PBMC. In plasma, we monitored reactive oxygen metabolites (d-ROMs) and ferric-reducing antioxidant power. In PBMC, we measured the expression of antioxidant enzymes SOD1, GPX1 and CAT by qPCR. Further, we evaluated the expression of inflammatory mediators such as IL6, TNF-α, CD68 and MCP1 by qPCR in PBMC.

RESULTS

T2DM patients exhibited elevated PAR levels in PBMC and increased d-ROMs in plasma. Positive associations were found between PAR levels and d-ROMs, suggesting a link between oxidative stress and altered PAR metabolism. Mediation analysis revealed that d-ROMs mediate the association between HbA1c levels and PAR, indicating oxidative stress as a potential driver of increased PARylation in T2DM. Furthermore, elevated PAR levels were found to be associated with increased expression of pro-inflammatory cytokines IL6 and TNF-α in the PBMC of T2DM patients.

CONCLUSIONS

This study highlights that hyperactivation of PARylation is associated with poor glycemic control and the resultant oxidative stress in T2DM. The increase of PAR levels is correlated with the upregulation of key mediators of the inflammatory response. Further research is warranted to validate these findings and explore their clinical implications.

Comparison of neutrophil to lymphocyte ratio, platelet to lymphocyte ratio, and C-reactive protein in predicting osteomyelitis in patients with diabetic foot ulcer

Introduction

Neutrophil/lymphocyte ratio (NLR) and platelet/ lymphocyte ratio (PLR) are readily available and inexpensive biomarkers that have received great attention for diagnosing type 2 diabetes(T2DM) complications. The objective of the present cross-sectional study was to compare diagnostic values of these biomarkers with C-reactive protein(CRP) in detecting diabetic foot ulcer (DFU) and osteomyelitis (OS) and discriminating between the degree of DFU according to Wagner's classification.

Methods

A total of 217 individuals (42 healthy controls, 40 T2DM patients without DFU, and 135 patients with DFU) were enrolled. The DFU patients were classified according to Wagner's classification into grade 1, grade 2, and grade 3. Blood samples were obtained and various biochemical and hematological parameters including creatine, CRP, HbA1c, NLR, and PLR were measured.

Results

The levels of CRP, PLR, and NLR were significantly higher in the patients with DFU and OS compared to healthy controls and T2DM patients without DFU. The median values of CRP were correlated with the severity of DFU and increased with DFU grades. The highest values of CRP, NLR, and PLR were observed in the DFU patients with OS which were significantly higher than those of DFU patients with grades 1 and 2 as well as T2DM patients without DFU. The PLR and NLR had no significant performance in diagnosing DFU patients with grades 1 and 2 from the patients without DFU.

Conclusion

NLR and PLR could be useful for diagnosing OS but cannot be used for detecting lower grades of DFU. CRP showed higher performance in detecting OS compared to PLR and NLR.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01327-w.

Significance of Neutrophil to Lymphocyte Ratio (NLR) and Platelet Lymphocyte Ratio (PLR) in Diabetic Foot Ulcer and Potential New Therapeutic Targets

Diabetic foot ulcer (DFU) is a well-known complication of diabetes and a significant burden on the national health systems. The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio are inexpensive and easily accessible biomarkers that have proved to be useful in several inflammatory, infectious and cardiovascular diseases. We carried out a comprehensive review examining the association of NLR and PLR with the onset and progression of DFU. PLR and NLR were significantly increased in patients with DFU, compared with a control group of T2DM patients without DFU, and correlate well with DFU severity, evaluated by Wagner and IWGDF grading scales. In patients with diabetic foot infections (DFI), elevated NLR and PLR were correlated with osteomyelitis, increased risk of amputation, and septic complications. The significance of the elevated value of these biomarkers in DFU is related to chronic hyperglycemia and low-grade systemic inflammation, atherosclerotic and vascular complications, and also the associated septic factor. Serial, dynamic follow-up can provide useful information in planning and monitoring DFU treatment, as well as in risk stratification of these vulnerable patients. Further randomized studies are needed to set the cut-off values with clinical significance.

Correlation between insulin resistance and the rate of neutrophils-lymphocytes, monocytes-lymphocytes, platelets-lymphocytes in type 2 diabetic patients

BACKGROUND

Insulin resistance (IR) was a prominent feature commonly observed in individuals with type 2 diabetes mellitus (T2DM). T2DM Individuals often exhibited a concomitant presence of low-grade chronic inflammation. In this study conducted retrospectively, the aim was to investigate the connection between neutrophils-lymphocytes rate (NLR), monocytes-lymphocytes rate (MLR), platelets-lymphocytes rate (PLR) and IR, specifically among individuals with T2DM.

METHOD

This study encompassed a cohort of 405 individuals diagnosed with T2DM, comprising cases from January 2021 to November 2022. On the basis of whether there was IR or not, these sufferers were categorized into two cohorts, namely T2DM with IR group (292 cases) and T2DM without IR group (113 cases), as determined by a homeostasis model assessment-IR (HOMA-IR) value exceeding 2.0.

RESULTS

The findings of this study demonstrated compelling evidence of distinct biomarker profiles between individuals with T2DM who had IR and those without IR. Specifically, the IR individuals displayed notably raise NLR, MLR, PLR, C reactive protein (CRP) and serum amyloid A (SAA). Additionally, there was a noticeable decrease in superoxide dismutase (SOD) levels. Furthermore, IR was negatively correlated with SOD values, while positive associations were found between IR and NLR, CRP, and SAA levels (p < 0.05). Moreover, a rise in NLR and PLR levels demonstrated an identical relationship with the prevalence of IR (p = 0.007, p = 0.025, separately). The Receiver operating characteristic (ROC) curve demonstrated that the areas under the curve (AUC) for NLR, MLR, PLR, CRP, SAA and SOD in predicting occurrence of IR in T2DM patients were 0.603, 0.575, 0.581, 0.644, 0.594 and 0.632 respectively, with sensitivity of 79.5%, 95.2%, 46.9%,54.1% (or 51.4), 47.6% (or 45.7%) and 98.6% and specificity of 37.2%, 19.5%, 69.9%, 69% (or 71.7%), 71.6% (or 73.5%) and 23% respectively.

CONCLUSION

Our findings support the notion that higher magnitude of NLR, PLR, MLR, CRP, and SAA values, corresponded to lower SOD levels, indicating a more severe degree of IR in T2DM patients. Additionally, NLR, PLR, MLR, CRP, SAA, and SOD demonstrated predictive potential for assessing IR. Regrettably, due to the retrospective nature of this study, it was not feasible to take a measurement the majority of inflammatory factors and reactive oxygen species (ROS).

When type II diabetes mellitus meets COVID-19-Identification of the shared gene signatures and biological mechanism between the two diseases

BACKGROUND

According to current studies, more than 20% of all patients diagnosed with COVID-19 globally have diabetes. Further, the mortality rate of these patients is 7.3%. Compared with non-diabetic COVID-19 patients, diabetic COVID-19 patients have higher rates of mortality and severe infection, suggesting that diabetes is associated with the severity of COVID-19 infection. This study aimed to analyse the relationship and susceptibility factors between COVID-19 and T2DM.

METHODS

Using bioinformatics methods, potential targets for COVID-19 and T2DM were screened from GeneCards database. Potential targets of COVID-19 and T2DM were mapped to each other to identify overlapping targets, and a PPI network was constructed to extract the core target. The clusterProfiler package in R was used to analyse the function and pathway that core target involved. GO enrichment and KEGG pathway analysis were used to elucidate the correlation between COVID-19 and T2DM.

RESULTS

A total of 277 potential pathogenic targets of COVID-19 were found, 282 potential targets were found for T2DM. Mapping of the potential COVID-19 and T2DM targets revealed 53 overlapping targets, with TNF as the core target. IL-17 signalling pathway was the most significant KEGG pathway involving TNF.

CONCLUSIONS

The inflammatory cytokine, TNF, was identified as a core target between COVID-19 and T2DM, which induces inflammatory response mainly through the IL-17 signalling pathway, leading to aggravation of infection and increased difficulty in blood glucose control. This study provides a reference for further exploring the potential correlation and endogenous mechanisms between two seemingly independent and unrelated diseases-T2DM and COVID-19.

Predictors of New-Onset Diabetes in Hospitalized Patients with SARS-CoV-2 Infection

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is one of the world's most disruptive health crises. The presence of diabetes plays an important role in the severity of the infection, and a rise in newly diagnosed diabetes cases has been identified. The aim of this retrospective study was to determine the incidence of new-onset diabetes (NOD) and predictive factors with their cut-off values for patients hospitalized with COVID-19. All patients (n = 219) hospitalized for COVID-19 during three consecutive months were included. NOD was diagnosed in 26.48% of patients. The severity of the infection, hospital admission values for fasting plasma glucose, lactate dehydrogenase (LDH), PaO2/FiO2 ratio, the peak values for leucocytes, neutrophils, C-reactive protein, triglycerides, and the need for care in the intensive care unit were predictors for the occurrence of NOD in univariate analysis, while only LDH level remained a significant predictor in the multivariable analysis. In conclusion, the results of the study showed a high incidence of NOD in patients hospitalized with COVID-19 and identified LDH levels at hospital admission as a significant predictor of NOD during SARS-CoV-2 infection. However, the persistence of NOD after the COVID-19 infection is not known, therefore, the results must be interpreted with caution.

Association Between the Neutrophil-To-Lymphocyte Ratio and Diabetes Secondary to Exocrine Pancreatic Disorders

Background

Diabetes mellitus among patients with exocrine pancreatic disorders is commonly known to be associated with chronic inflammation, including chronic pancreatitis and pancreatic ductal adenocarcinoma (PDAC). The neutrophil-to-lymphocyte ratio (NLR) is a novel marker that indicates the presence of various chronic inflammatory diseases, including type 2 diabetes (T2DM). However, no studies have examined the relationship between the NLR value and diabetes secondary to exocrine pancreatic disorders.

Aim

To determine whether the NLR value is associated with diabetes secondary to exocrine pancreatic disorders.

Methods

The medical data of subjects with confirmed pancreatic disease who were admitted to the Department of Pancreatic Surgery of our institution from August 2017 to October 2021 were obtained from the database and retrospectively analyzed. Anthropometric measures, laboratory data, including HbA1c, fasting insulin, and fasting C-peptide levels and the inflammatory index (white blood cell count, NLR, platelet-to-lymphocyte ration, monocyte-to-lymphocyte ratio) were recorded. The NLR is the ratio of neutrophils to lymphocytes. A homeostasis model (HOMA-B and HOMA-IR) was used to measure beta-cell dysfunction and insulin resistance.

Results

The NLR values of the diabetes secondary to exocrine pancreatic disorders group were significantly higher than those of the nondiabetic group (P=0.001). In multivariate logistic regression, after adjusting for covariates, high NLR values were found to be an independent risk factor for diabetes secondary to exocrine pancreatic disorders (OR: 1.37, 95% CI: 1.138-1.649, P=0.001). According to Spearman correlation analysis, the NLR was significantly correlated with fasting plasma glucose levels (P<0.0001) and HOMA2-IR values (P=0.02).

Conclusion

The NLR inflammation marker was significantly higher in subjects with diabetes secondary to exocrine pancreatic disorders and was associated with insulin resistance. NLR values may be reliable predictive markers for diabetes among patients with exocrine pancreatic disorders.

Mechanisms underlying the pathophysiology of type 2 diabetes: From risk factors to oxidative stress, metabolic dysfunction, and hyperglycemia

Type 2 diabetes (T2D) is a complex multifactorial disease that emerges from the combination of genetic and environmental factors, and obesity, lifestyle, and aging are the most relevant risk factors. Hyperglycemia is the main metabolic feature of T2D as a consequence of insulin resistance and β-cell dysfunction. Among the cellular alterations induced by hyperglycemia, the overproduction of reactive oxygen species (ROS) and consequently oxidative stress, accompanied by a reduced antioxidant response and impaired DNA repair pathways, represent essential mechanisms underlying the pathophysiology of T2D and the development of late complications. Mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and inflammation are also closely correlated with insulin resistance and β-cell dysfunction. This review focus on the mechanisms by which oxidative stress, mitochondrial dysfunction, ER stress, and inflammation are involved in the pathophysiology of T2D, highlighting the importance of the antioxidant response and DNA repair mechanisms counteracting the development of the disease. Moreover, we indicate evidence on how nutritional interventions effectively improve diabetes care. Additionally, we address key molecular characteristics and signaling pathways shared between T2D and Alzheimer's disease (AD), which might probably be implicated in the risk of T2D patients to develop AD.

Increased PARylation impacts the DNA methylation process in type 2 diabetes mellitus

Background

Epigenetic modifications, such as DNA methylation, can influence the genetic susceptibility to type 2 diabetes mellitus (T2DM) and the progression of the disease. Our previous studies demonstrated that the regulation of the DNA methylation pattern involves the poly(ADP-ribosyl)ation (PARylation) process, a post-translational modification of proteins catalysed by the poly(ADP-ribose) polymerase (PARP) enzymes. Experimental data showed that the hyperactivation of PARylation is associated with impaired glucose metabolism and the development of T2DM. Aims of this case–control study were to investigate the association between PARylation and global and site-specific DNA methylation in T2DM and to evaluate metabolic correlates.

Results

Data were collected from 61 subjects affected by T2DM and 48 healthy individuals, recruited as controls. Global levels of poly(ADP-ribose) (PAR, a surrogate of PARP activity), cytosine methylation (5-methylcytosine, 5mC) and de-methylation intermediates 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) were determined in peripheral blood cells by ELISA-based methodologies. Site-specific DNA methylation profiling of SOCS3, SREBF1 and TXNIP candidate genes was performed by mass spectrometry-based bisulfite sequencing, methyl-sensitive endonucleases digestion and by DNA immuno-precipitation. T2DM subjects presented higher PAR levels than controls. In T2DM individuals, increased PAR levels were significantly associated with higher HbA1c levels and the accumulation of the de-methylation intermediates 5hmC and 5fC in the genome. In addition, T2DM patients with higher PAR levels showed reduced methylation with increased 5hmC and 5fC levels in specific SOCS3 sites, up-regulated SOCS3 expression compared to both T2DM subjects with low PAR levels and controls.

Conclusions

This study demonstrates the activation of PARylation processes in patients with T2DM, particularly in those with poor glycaemic control. PARylation is linked to dysregulation of DNA methylation pattern via activation of the DNA de-methylation cascade and may be at the basis of the differential gene expression observed in presence of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01099-1.

Diabetes is associated with higher mortality and severity in hospitalized patients with COVID-19

As a novel cause of pneumonia, coronavirus disease 2019 (COVID-19) has rapidly progressed worldwide. Previous studies have indicated COVID-19 patients with diabetes show higher mortality rates and more severe COVID-19 infection with an increased requirement for intensive care and hospital length of stay (LOS) compared to non-diabetic patients. The present study aimed to investigate the association of diabetes and COVID-19 outcome with severity of disease in hospitalized patients. The present case-control study included 268 patients diagnosed with COVID-19 who were hospitalized in Ayatollah Khoyi Hospital, Khoy, Iran. Diabetes was identified based on medical history and/or criteria of published documents. Out of 268 patients (median age of 59 years; 53.4 % male), 127 patients had diabetes (47 %). Diabetic patients had remarkably higher mortality rates (adjusted odds ratio, aOR: 3.36; confidence interval, CI: 1.17-9.66), requirement for invasive mechanical ventilation (IMV) (aOR: 4.59; CI: 1.38-15.25), and LOS (aOR: 1.13; CI: 1.06-1.24) compared to patients without diabetes. Inflammatory biomarkers including C-reactive protein (CRP), lactate dehydrogenase (LDH), and erythrocyte sedimentation rate (ESR) were increased in patients with diabetes compared to non-diabetic patients (P < 0.05 for all the comparisons). In hospitalized patients with COVID-19, diabetes was correlated with increased disease severity and mortality.

Correlation between the platelet-to-lymphocyte ratio and diabetic foot ulcer in patients with type 2 diabetes mellitus

OBJECTIVE

To investigate the correlation between the platelet-to-lymphocyte ratio (PLR) and diabetic foot ulcer (DFU) in patients with type 2 diabetes mellitus (T2DM).

METHOD

From January 2018 to August 2019, 206 patients with T2DM admitted to the Central Hospital of Wuhan, China, were enrolled in this study, including 104 patients with DFU (DFU group) and 102 patients without DFU (T2DM group). During the same period, 90 healthy subjects were randomly screened as normal controls (NC group). The correlation between PLR and DFU in patients with T2DM was explored by comparing the PLR of the subjects in the three groups.

RESULTS

The PLRs of the DFU and T2DM groups were higher than that of the NC group, whereas the PLR of the DFU group was higher than that of the T2DM group (p < 0.05). PLR was positively correlated with the Wagner DFU grade (p < 0.001). Based on logistic regression analysis, PLR was found to be an independent risk factor for DFU (OR =1.029, 95% CI: 1.019 ~ 1.039, p < 0.001). The receiver operating characteristic curve analysis of the PLR showed that the area under the curve of the PLR for predicting diabetic foot ulcer was 0.776 (p < 0.001), and the analysis determined that the optimal critical value of the PLR for predicting DFU was 147.6.

CONCLUSION

The PLR is significantly elevated in patients with DFU and positively correlated with the Wagner DFU grade, which might be a valuable marker for early diagnosis and assessment of severity of DFU.

Melatonin supplementation over different time periods until ageing modulates genotoxic parameters in mice

The ageing process is a multifactorial phenomenon, associated with decreased physiological and cellular functions and an increased propensity for various degenerative diseases. Studies on melatonin (N-acetyl-5-methoxytryptamine), a potent antioxidant, are gaining attention since melatonin production declines with advancing age. Hence, the aim of this study was to evaluate the effects of chronic melatonin consumption on genotoxic and mutagenic parameters of old Swiss mice. Herein, 3-month-old Swiss albino male mice (n = 240) were divided into eight groups and subdivided into two experiments: first (three groups): natural ageing experiment; second (five groups): animals that started water or melatonin supplementation at different ages (3, 6, 12 and 18 months) until 21 months. After 21 months, the animals from the second experiment were euthanized to perform the comet assay, micronucleus test and western blot analysis. The results demonstrated that melatonin prolonged the life span of the animals. Relative to genomic instability, melatonin was effective in reducing DNA damage caused by ageing, presenting antigenotoxic and antimutagenic activities, independently of initiation age. The group receiving melatonin for 18 months had high levels of APE1 and OGG1 repair enzymes. Conclusively, melatonin presents an efficient antioxidant mechanism aiding modulating genetic and physiological alterations due to ageing.

Identification of stress-related microRNA biomarkers in type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Many studies have investigated microRNAs (miRNAs) in the detection of type 2 diabetes mellitus (T2DM). Herein, the dysregulated direction of stress-related miRNAs used as biomarkers of T2DM are summarized and analyzed.

METHODS

PubMed, EMBASE, ISI Web of Science, and three Chinese databases were searched for case-control miRNA profiling studies about T2DM. A meta-analysis under a random effect was performed. Subgroup analysis was conducted based on different tissues and species. Sensitivity analysis was conducted to confirm the robustness among studies. The effect size was pooled using ln odds ratios (ORs), 95% confidence intervals (95% CIs), and P-values.

RESULTS

The present meta-analysis included 39 case-control studies with a total of 494 miRNAs. Only 33 miRNAs were reported in three or more studies and, of these, 18 were inconsistent in their direction of dysregulation. Two significantly dysregulated miRNAs (let-7 g and miR-155) were identified in the meta-analysis. Four miRNAs (miR-142-3p, miR-155, miR-21, and miR-34c-5p) were dysregulated in patients with T2DM, whereas five miRNAs (miR-146a, miR-199a-3p, miR-200b, miR-29b and miR-30e) were dysregulated in animal models of diabetes. In addition, two dysregulated miRNAs (miR-146a and miR-21) were highly cornea specific and heart specific. In sensitivity analysis, only miR-155 was still significantly dysregulated after removing studies with small sample sizes.

CONCLUSIONS

The present meta-analysis revealed that 16 stress-related miRNAs were significantly dysregulated in T2DM. MiR-148b, miR-223, miR-130a, miR-19a, miR-26b and miR-27b were selected as potential circulating biomarkers of T2DM. In addition, miR-146a and miR-21 were identified as potential tissue biomarkers of T2DM.

Poly(ADP-Ribose) Polymerase Activity and Coronary Artery Disease in Type 2 Diabetes Mellitus: An Observational and Bidirectional Mendelian Randomization Study

OBJECTIVE

Experimental evidence suggests a close link between PARP (poly[ADP-ribose] polymerase) activation and diabetic endothelial dysfunction. Here, we tested whether PARP activity in circulating leukocytes was associated with coronary artery disease (CAD) among patients with type 2 diabetes mellitus (T2DM). Approach and Results: We performed observational and bidirectional Mendelian randomization studies of 3149 Chinese individuals with T2DM who underwent coronary angiography, with leukocyte PARP activity, 16 tag single-nucleotide polymorphisms in PARP1 and PARP2, and 17 CAD risk single-nucleotide polymorphisms analyzed. Of 3149 participants, 1180 who further received percutaneous coronary intervention were prospectively followed for 1 year to track major adverse cardiovascular and cerebrovascular events. Overall, greater PARP activity was cross-sectionally associated with an odds ratio of 1.23 for obstructive CAD, and prospectively with a hazard ratio of 1.34 for 1-year major adverse cardiovascular and cerebrovascular events after percutaneous coronary intervention (both P<0.001). Using a genetic score of 5 screened single-nucleotide polymorphisms in PARP1 and PARP2 as the instrumental variable, genetically predicted elevation in PARP activity showed a causal association with obstructive CAD (odds ratio=1.35, P<0.001). In contrast, the genetic risk of CAD had no significant effect on PARP activity. Ex vivo and in vitro cultures of human monocytes showed that rs747657, as the lead single-nucleotide polymorphism strongly associated with PARP activity, caused the differential binding of transcription factor GATA2 (GATA-binding protein 2) to an intronic regulatory region in PARP1, thus modulating PARP1 expression and PARP activity.

CONCLUSIONS

Greater PARP activity may have causal roles in the development of obstructive CAD among patients with diabetes mellitus.

The role of exercise in brain DNA damage

Cells are constantly subjected to cytotoxic and genotoxic insults resulting in the accumulation of unrepaired damaged DNA, which leads to neuronal death. In this way, DNA damage has been implicated in the pathogenesis of neurological disorders, cancer, and aging. Lifestyle factors, such as physical exercise, are neuroprotective and increase brain function by improving cognition, learning, and memory, in addition to regulating the cellular redox milieu. Several mechanisms are associated with the effects of exercise in the brain, such as reduced production of oxidants, up-regulation of antioxidant capacity, and a consequent decrease in nuclear DNA damage. Furthermore, physical exercise is a potential strategy for further DNA damage repair. However, the neuroplasticity molecules that respond to different aspects of physical exercise remain unknown. In this review, we discuss the influence of exercise on DNA damage and adjacent mechanisms in the brain. We discuss the results of several studies that focus on the effects of physical exercise on brain DNA damage.

Elevated fasting serum glucose levels increase the risk of hepatocellular carcinoma: A prospective cohort study

Previous studies have demonstrated a positive relationship between liver cancer and diabetes mellitus. However, elevated fasting blood glucose (FBG) itself may be a risk factor for the development of hepatocellular carcinoma (HCC) rather than diabetes, and during the follow-up period, death is an event that may occur before the occurrence of HCC, which should be dealt with competing risk models. Our study aims to investigate the relationship between FBG and new-onset HCC by using competing risk regression models.We prospectively studied the relationship between FBG concentrations and risk of HCC in a cohort of 93,447 participants who were free of prior HCC, and whose demographic characteristics and biochemical parameters were recorded. Cox proportional hazards regression models and competing risk regression models were used to evaluate the association between FBG concentrations and risk of incident HCC.A total of 302 participants were diagnosed with HCC among 93,447 subjects during 810,499 person-years of follow-up. The multivariable hazard ratios (HRs) [95% confidence interval (95% CI)] for the association of FBG and log(FBG) with HCC were 1.07 (1.01∼1.12), 1.84 (1.23∼2.74) in an analysis adjusted for other potential variables. In the multivariable adjusted analysis, participants who were in 4.82 mmol/L≤FBG≤5.49 mmol/L group and FBG >5.49 mmol/L group would have increased the risk of HCC by 47% and 69%, respectively. In a cause-specific hazard model (CS model), the multivariable HRs (95% CI) for the association of FBG with HCC were 1.46 (1.09∼1.98), 1.69 (1.27∼2.27) in the multivariable adjusted analysis. Similar results were also observed in sub-distribution hazard function model (SD model) with corresponding multivariate HRs (95% CI) of 1.46 (1.09∼2.00), 1.69 (1.25∼2.27) in 4.82 mmol/L≤FBG≤5.49 mmol/L group and FBG >5.49 mmol/L group, respectively.Higher FBG concentrations itself were positively associated with new-onset HCC in the Cox proportional hazards regression models and competing risk models. FBG concentrations can be used as a scientific and important way to identify individuals with a higher risk of HCC and control of FBG concentrations might serve as a possible way to decrease the risk of HCC among Chinese population.Trial registration: ChiCTR-TNRC-11001489. Registered August 24, 2011 (retrospectively registered).

ADP-ribosylation signalling and human disease

ADP-ribosylation (ADPr) is a reversible post-translational modification of proteins, which controls major cellular and biological processes, including DNA damage repair, cell proliferation and differentiation, metabolism, stress and immune responses. In order to maintain the cellular homeostasis, diverse ADP-ribosyl transferases and hydrolases are involved in the fine-tuning of ADPr systems. The control of ADPr network is vital, and dysregulation of enzymes involved in the regulation of ADPr signalling has been linked to a number of inherited and acquired human diseases, such as several neurological disorders and in cancer. Conversely, the therapeutic manipulation of ADPr has been shown to ameliorate several disorders in both human and animal models. These include cardiovascular, inflammatory, autoimmune and neurological disorders. Herein, we summarize the recent findings in the field of ADPr, which support the impact of this modification in human pathophysiology and highlight the curative potential of targeting ADPr for translational and molecular medicine.

The impact of insulin pump therapy to oxidative stress in patients with diabetic nephropathy

Background

The oxidative stress resulting from increased production of ROS plays a crucial role in the development of diabetic complications. We aim to explore the relationships between oxidative stress, diabetic nephropathy (DN) and short-term insulin pump intensive therapy (insulin therapy).

Methods

Levels of 8-hydroxy-deoxyguanosine (8-OHdG), 3-nitrotyrosine (3-NT), glutathione (GSH), superoxide dismutase (SOD) and Interleukin-6 (IL-6) were estimated before and after 2 weeks of insulin therapy in normal group (NC) and type 2 diabetic (DM) with normal albuminuria (NA), microalbuminuria (MA) and clinical albuminuria (CA).

Results

In DM group, levels of 8-OHdG and 3-NT were higher than those in NC group (P < 0.05); GSH and SOD were lower (P < 0.05). And their levels changed with urine albumin–creatinine ratio (P < 0.05). After insulin therapy, these derangements were significantly ameliorated and the changes in NA and MA groups were more significant than CA group (P < 0.05). Correlation analysis showed glycated hemoglobin, the course of disease, the HOME-IR and fasting plasma glucose were positively correlated with 8-OHdG and 3-NT, but negatively correlated with GSH and SOD.

Conclusions

The oxidative stress gradually increased with the magnitude of DN, and insulin pump intensive therapy can significantly ameliorate the derangements in the early stage of DN.

Trial registration NCT03174821

Association of Fasting Glucose Level with Neutrophil-Lymphocyte Ratio Compared to Leukocyte Count and Serum C-Reactive Protein

Background

The neutrophil-lymphocyte ratio (NLR) is often used as an inflammatory marker in chronic diseases such as cancer or cardiovascular diseases. However, there are few studies about the association between the NLR and diabetes mellitus (DM) or impaired fasting glucose (IFG) patients in Korea. This study investigated the association between the fasting plasma glucose (FPG) level and NLR in Koreans.

Methods

This cross-sectional retrospective study included 3,219 healthy subjects who visited Konyang University Hospital in South Korea for regular health examinations. Participants with a history of insulin administration, anti-diabetic drugs, anti-inflammatory drugs, or underlying diseases related to inflammation were excluded.

Results

All statistical evaluation was performed by dividing participants into males and females. Based on FPG levels, the subjects were classified into three groups, with normal fasting glucose (n=1,969), IFG (n=1,138), and DM (n=122). The NLR had no significant mean differences among these groups for both sexes. Multiple linear regression analysis between FPG level and NLR showed an independent and significantly negative association (β±standard error, −0.67±0.24; P=0.006) in normal subjects after adjustment. Log(serum C-reactive protein [S-CRP]) showed an independently and significantly positive association with FPG in male IFG/DM patients. Total leukocyte (white blood cell [WBC]) showed an independently and significantly positive association with FPG in female IFG/DM patients.

Conclusion

In normal subjects, NLR shows an independently and significantly negative association with FPG. In IFG/DM patients, NLR was not significantly related to FPG. WBC count in female patients and S-CRP level in male patients were significantly positively associated with FPG only in IFG/DM.

PARP-1 Variant Rs1136410 Confers Protection against Coronary Artery Disease in a Chinese Han Population: A Two-Stage Case-Control Study Involving 5643 Subjects

Inhibition of poly(ADP-ribose) polymerase (PARP) may protect against coronary artery disease (CAD) in animal models, and rs1136410, a non-synonymous single nucleotide polymorphism (SNP) in PARP-1, has a potential impact on PARP activities in vitro. This two-stage case-control study, involving 2803 CAD patients and 2840 controls, aimed to investigate the associations of PARP-1 rs1136410 with CAD development, lipid levels, PARP activities, 8-hydroxy-2'-dexyguanosine (8-OHdG), and interleukin (IL)-6 levels in a Chinese Han population. Assuming a recessive model, the variant genotype GG of SNP rs1136410 showed a significantly inverse association with CAD risk (adjusted odds ratio (OR) = 0.73, P < 0.001), left main coronary artery (LMCA) lesions (P = 0.003), vessel scores (P = 0.003), and modified Gensini scores (P < 0.001). There were significant correlations of SNP rs1136410 with higher levels of total cholesterol (TC) and lower levels of high-density lipoprotein cholesterol (HDL-c). In gene-environment interaction analyses, participants with the variant genotype GG, but without smoking habit, type 2 diabetes mellitus, and hyperlipidemia, conferred an 84% (P < 0.001) decreased risk of CAD. The genotype-phenotype correlation analyses further supported the functional roles of SNP rs1136410 in decreasing PARP activities and 8-OHdG levels. Taken together, our data suggest that SNP rs1136410 may confer protection against CAD through modulation of PARP activities and gene-environment interactions in a Chinese Han population.

Antidepressant-Like Actions of Inhibitors of Poly(ADP-Ribose) Polymerase in Rodent Models

BACKGROUND

Many patients suffering from depressive disorders are refractory to treatment with currently available antidepressant medications, while many more exhibit only a partial response. These factors drive research to discover new pharmacological approaches to treat depression. Numerous studies demonstrate evidence of inflammation and elevated oxidative stress in major depression. Recently, major depression has been shown to be associated with elevated levels of DNA oxidation in brain cells, accompanied by increased gene expression of the nuclear base excision repair enzyme, poly(ADP-ribose) polymerase-1. Given these findings and evidence that drugs that inhibit poly(ADP-ribose) polymerase-1 activity have antiinflammatory and neuroprotective properties, the present study was undertaken to examine the potential antidepressant properties of poly(ADP-ribose) polymerase inhibitors.

METHODS

Two rodent models, the Porsolt swim test and repeated exposure to psychological stressors, were used to test the poly(ADP-ribose) polymerase inhibitor, 3-aminobenzamide, for potential antidepressant activity. Another poly(ADP-ribose) polymerase inhibitor, 5-aminoisoquinolinone, was also tested.

RESULTS

Poly(ADP-ribose) polymerase inhibitors produced antidepressant-like effects in the Porsolt swim test, decreasing immobility time, and increasing latency to immobility, similar to the effects of fluoxetine. In addition, 3-aminobenzamide treatment increased sucrose preference and social interaction times relative to vehicle-treated control rats following repeated exposure to combined social defeat and unpredictable stress, mediating effects similar to fluoxetine treatment.

CONCLUSIONS

The poly(ADP-ribose) polymerase inhibitors 3-aminobenzamide and 5-aminoisoquinolinone exhibit antidepressant-like activity in 2 rodent stress models and uncover poly(ADP-ribose) polymerase as a unique molecular target for the potential development of a novel class of antidepressants.

Elevated DNA Oxidation and DNA Repair Enzyme Expression in Brain White Matter in Major Depressive Disorder

BACKGROUND

Pathology of white matter in brains of patients with major depressive disorder (MDD) is well-documented, but the cellular and molecular basis of this pathology are poorly understood.

METHODS

Levels of DNA oxidation and gene expression of DNA damage repair enzymes were measured in Brodmann area 10 (BA10) and/or amygdala (uncinate fasciculus) white matter tissue from brains of MDD (n=10) and psychiatrically normal control donors (n=13). DNA oxidation was also measured in BA10 white matter of schizophrenia donors (n=10) and in prefrontal cortical white matter from control rats (n=8) and rats with repeated stress-induced anhedonia (n=8).

RESULTS

DNA oxidation in BA10 white matter was robustly elevated in MDD as compared to control donors, with a smaller elevation occurring in schizophrenia donors. DNA oxidation levels in psychiatrically affected donors that died by suicide did not significantly differ from DNA oxidation levels in psychiatrically affected donors dying by other causes (non-suicide). Gene expression levels of two base excision repair enzymes, PARP1 and OGG1, were robustly elevated in oligodendrocytes laser captured from BA10 and amygdala white matter of MDD donors, with smaller but significant elevations of these gene expressions in astrocytes. In rats, repeated stress-induced anhedonia, as measured by a reduction in sucrose preference, was associated with increased DNA oxidation in white, but not gray, matter.

CONCLUSIONS

Cellular residents of brain white matter demonstrate markers of oxidative damage in MDD. Medications that interfere with oxidative damage or pathways activated by oxidative damage have potential to improve treatment for MDD.

Association of neutrophil-lymphocyte ratio with metabolic syndrome and its components in Asian Indians (CURES-143)

BACKGROUND

Metabolic syndrome (MS) is the state of chronic low grade inflammation. This study looks at the relationship of neutrophil-lymphocyte ratio (NLR) in subjects with and without MS in Asian Indians.

METHODS

Study subjects (n=754) were recruited from the Chennai Urban Rural Epidemiology Study. MS was defined using the National Cholesterol Education Program-Adult Treatment Panel (NCEP-ATP) III criteria modified for waist according to World Health Organization Asia Pacific guidelines. A complete hemogram was done in all subjects using a five-part hematology analyzer (model SF-3000; Sysmex, Kobe, Japan). The NLR was calculated as the ratio between counts for neutrophils and total lymphocytes in subjects with (n=422) and without (n332) MS and correlated with number of metabolic abnormalities in those with MS.

RESULTS

Subjects with five metabolic abnormalities had the highest NLR, and with decreasing number of metabolic abnormalities, the NLR decreased linearly (p for trend <0.001). Logistic regression analysis revealed that even after adjusting for age, gender and body mass index, MS was strongly associated with NLR (p<0.001).

CONCLUSION

Among Asian Indians, NLR is correlated with MS and also with the number of metabolic abnormalities.

The association of hematologic inflammatory markers with atherogenic index in type 2 diabetic retinopathy patients

BACKGROUND

Atherogenic dyslipidemia is particularly common in people with type 2 diabetes (DM2). Platelets from patients with DM2 have increased reactivity and baseline activation. The aim of the present study is to evaluate the relationship between atherogenic index and hematologic inflammatory markers and to evaluate the relationship between these parameters and associated variables in diabetic retinopathy (DR) patients.

METHODS

The medical records of all patients admitted to the eye clinic between January and December 2014 were evaluated systematically. Laboratory parameters of 278 outpatients with DM2 diagnosed after the age of 30 years and 107 healthy subjects were analyzed.

RESULTS

The DM2 + DR group consisted of 120 patients (47 males and 73 females; mean age 59.8±9.2 years). The DM2 without DR group consisted of 158 patients (59 males and 99 females; mean age 57.3±12.2 years). Mean platelet volume, platelet distribution width (PDW), platelet-lymphocyte (P/L) ratio, triglycerides, and atherogenic index were higher in DM2 patients than in control patients, but there was no difference between the DM2 + DR and the DM2 without DR groups. Only P/L ratio was different in the DM2 + DR patients compared to the DM2 without DR patients. Hemoglobin A1c levels correlated very weakly with the mean platelet volume, PDW, P/L ratio, and the red cell distribution width. The atherogenic index was very weakly correlated with the P/L ratio, PDW, and red cell distribution width.

CONCLUSION

Dyslipidemia-induced inflammation contributes to pathological processes that lead to retinopathy in DR patients.

Increased 8-hydroxy-2'-deoxyguanosine in leukocyte DNA from patients with type 2 diabetes and microangiopathy

Objective

To evaluate oxidative damage in leukocytes from patients with type 2 diabetes by examining 8-hydroxy-2’-deoxyguanosine (8-OHdG) levels.

Methods

Patients with type 2 diabetes and healthy controls were assessed for demographic, clinical and biochemical characteristics. Levels of 8-OHdG in extracted leukocyte DNA were determined by enzyme linked immunosorbent assay.

Results

Of 108 patients with type 2 diabetes (56 with microangiopathy, 52 without) and 65 healthy controls, leukocyte 8-OHdG levels were higher in patients with type 2 diabetes versus controls (median ± interquartile range [IQR], 3.19 ± 2.17 versus 0.38 ± 1.00 ng/ml), and higher in patients with type 2 diabetes and microangiopathy versus those without microangiopathy (median ± IQR, 3.34 ± 1.87 versus 2.71 ± 2.26 ng/ml). Patients with type 2 diabetes and microangiopathy had higher serum creatinine and urinary albumin levels versus those without microangiopathy. Leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria, use of insulin and use of angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) were independently associated with microangiopathy in patients with type 2 diabetes after adjustment for smoking.

Conclusions

Leukocyte oxidative DNA damage was high in patients with type 2 diabetes and microangiopathy. Presence of microangiopathy was associated with leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria and use of ACE inhibitors/ARBs or insulin.

Platelet-to-Lymphocyte Ratio: A Novel Prognostic Factor for Prediction of 90-day Outcomes in Critically Ill Patients With Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA) is a life-threatening acute complication of diabetes mellitus and the novel systemic inflammation marker platelet-to-lymphocyte ratio (PLR) may be associated with clinical outcome in patients with DKA. This study aimed to investigate the utility of PLR in predicting 90-day clinical outcomes in patients with DKA. Patient data exacted from the Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC II) database was analyzed. A cutoff value for PLR of 267.67 was determined using Youden index (P < 0.05) and used to categorize subjects into a high PLR group and a low PLR group. The hazard ratios (HRs) and 95% confidence intervals (CIs) for DKA were calculated across PLR. Clinical outcomes in our study were defined as intensive care unit (ICU) 90-day readmission and all-cause mortality. A total of 278 ICU admissions were enrolled and stratified by cutoff value of PLR. The incidence of readmission and mortality was 17.8% in the high PLR group, significantly higher than 7.4% in the low PLR group. In the multivariable model, after adjusting for known confounding variables including clinical parameters, comorbidities, laboratory parameters, the HRs for DKA were 2.573 (95% CI 1.239-5.345; P = 0.011), 2.648 (95% CI 1.269-5.527; P = 0.009), and 2.650 (95% CI 1.114-6.306; P = 0.028), respectively. The Kaplan-Meier survival curve showed that a high PLR level was associated with a higher risk for 90-day outcomes in patients with DKA. The authors report that higher PLR presents a higher risk for 90-day incidence of readmission and mortality in patients with DKA. It appears to be a novel independent predictor of 90-day outcomes in critically ill DKA patients in ICU units.

Recurrent hypoinsulinemic hyperglycemia in neonatal rats increases PARP-1 and NF-κB expression and leads to microglial activation in the cerebral cortex

BACKGROUND

Hyperglycemia is a common metabolic problem in extremely low-birth-weight preterm infants. Neonatal hyperglycemia is associated with increased mortality and brain injury. Glucose-mediated oxidative injury may be responsible. Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme involved in DNA repair and cell survival. However, PARP-1 overactivation leads to cell death. NF-κB is coactivated with PARP-1 and regulates microglial activation. The effects of recurrent hyperglycemia on PARP-1/NF-κB expression and microglial activation are not well understood.

METHODS

Rat pups were subjected to recurrent hypoinsulinemic hyperglycemia of 2 h duration twice daily from postnatal (P) day 3-P12 and killed on P13. mRNA and protein expression of PARP-1/NF-κB and their downstream effectors were determined in the cerebral cortex. Microgliosis was determined using CD11 immunohistochemistry.

RESULTS

Recurrent hyperglycemia increased PARP-1 expression confined to the nucleus and without causing PARP-1 overactivation and cell death. NF-κB mRNA expression was increased, while IκB mRNA expression was decreased. inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) mRNA expressions were decreased. Hyperglycemia significantly increased the number of microglia.

CONCLUSION

Recurrent hyperglycemia in neonatal rats is associated with upregulation of PARP-1 and NF-κB expression and subsequent microgliosis but not neuronal cell death in the cerebral cortex.

Effects of combined aerobic and resistance training on the glycolipid metabolism and inflammation levels in type 2 diabetes mellitus

[Purpose] To investigate the effects of combined aerobic and resistance training on glycolipid metabolism and inflammation levels in type 2 diabetes mellitus patients. [Subjects and Methods] Forty-two diabetes patients were randomized to the conventional therapy group (n = 20) or intensive therapy group (n = 22). The control group contained 20 healthy people. The conventional therapy group received routine drug therapy and diet control, while the intensive therapy group additionally underwent combined aerobic and resistance training for 12 weeks. The oral glucose tolerance test and cardiopulmonary exercise testing were performed. Toll-like receptor 4 and NF-κBp65 protein and mRNA expressions were determined by qPCR and western blotting. ELISA was used to determine the expression levels of interleukin-18, interleukin-33, pentraxin-related protein 3, and human cartilage glycoprotein 39. [Results] After exercise training, the intensive therapy group had significantly lower postprandial blood glucose, postprandial insulin, and glycated hemoglobin level and insulin resistance index than the conventional therapy group. The intensive therapy group had significantly lower toll-like receptor 4 and NF-κBp65 protein and mRNA expressions, and serum interleukin-18 levels but significantly higher serum interleukin-33 levels. [Conclusion] Combined aerobic and resistance training can improve glycolipid metabolism and reduce low-grade inflammation in patients with diabetes mellitus patients.

Protective Pleiotropic Effect of Flavonoids on NAD⁺ Levels in Endothelial Cells Exposed to High Glucose

NAD⁺ is important for oxidative metabolism by serving as an electron transporter. Hyperglycemia decreases NAD⁺ levels by activation of the polyol pathway and by overactivation of poly(ADP-ribose)-polymerase (PARP). We examined the protective role of three structurally related flavonoids (rutin, quercetin, and flavone) during high glucose conditions in an in vitro model using human umbilical vein endothelial cells (HUVECs). Additionally we assessed the ability of these flavonoids to inhibit aldose reductase enzyme activity. We have previously shown that flavonoids can inhibit PARP activation. Extending these studies, we here provide evidence that flavonoids are also able to protect endothelial cells against a high glucose induced decrease in NAD⁺. In addition, we established that flavonoids are able to inhibit aldose reductase, the key enzyme in the polyol pathway. We conclude that this protective effect of flavonoids on NAD⁺ levels is a combination of the flavonoids ability to inhibit both PARP activation and aldose reductase enzyme activity. This study shows that flavonoids, by a combination of effects, maintain the redox state of the cell during hyperglycemia. This mode of action enables flavonoids to ameliorate diabetic complications.

One-week intervention period led to improvements in glycemic control and reduction in DNA damage levels in patients with type 2 diabetes mellitus

AIMS

Hyperglycemia leads to increased production of reactive oxygen species (ROS), which reduces cellular antioxidant defenses and induces several DNA lesions. We investigated the effects on DNA damage of a seven-day hospitalization period in patients with type 2 diabetes mellitus (T2DM) to achieve adequate blood glucose levels through dietary intervention and medication treatment, compared with non-diabetic individuals.

METHODS

DNA damage levels were evaluated by the alkaline comet assay (with modified and without conventional use of hOGG1 enzyme, which detects oxidized DNA bases) for 10 patients and 16 controls. Real time PCR array method was performed to analyze the transcriptional expression of a set of 84 genes implicated in antioxidant defense and response to oxidative stress in blood samples from T2DM patients (n=6) collected before and after the hospitalization period.

RESULTS

The seven-day period was sufficient to improve glycemic control and to significantly decrease (p<0.05) DNA damage levels in T2DM patients, although those levels were slightly higher than those in control subjects. We also found a tendency towards a decrease in the levels of oxidative DNA damage in T2DM patients after the hospitalization period. However, for all genes analyzed, a statistically significant difference in the transcriptional expression levels was not observed.

CONCLUSIONS

The study demonstrated that although the transcriptional expression of the genes studied did not show significant alterations, one-week of glycemic control in hospital resulted in a significant reduction in DNA damage levels detected in T2DM patients, highlighting the importance of an adequate glycemic control.

Association of neutrophil-lymphocyte ratio with glucose intolerance: an indicator of systemic inflammation in patients with type 2 diabetes

BACKGROUND

The neutrophil-lymphocyte ratio (NLR) has been demonstrated to be a better risk factor than total white blood cell count in the prediction of adverse outcomes in various medical conditions. This study analyzed the association of NLR with different grades of glucose tolerance and insulin resistance in Asian Indians.

SUBJECTS AND METHODS

Study subjects were recruited from Phase 3 of the Chennai Urban Rural Epidemiology Study (CURES). For this cross-sectional analysis, subjects with normal glucose tolerance (NGT) (n=237), impaired glucose tolerance (IGT) (n=63), and type 2 diabetes mellitus (DM) (n=286) were selected. The hemogram was done in all subjects using a five-part hematology analyzer (model SF-3000; Sysmex, Kobe, Japan). The NLR was calculated as the ratio between counts for neutrophils and total lymphocytes. Fasting insulin was measured by enzyme-linked immunosorbent assay, and insulin resistance was calculated using the homeostasis model assessment (HOMA-IR).

RESULTS

Subjects with DM showed a significantly higher NLR (2.2 ± 1.12) compared with IGT subjects (1.82 ± 0.63), who in turn had a higher ratio than NGT subjects (1.5 ± 0.41) (P<0.01). Pearson correlation analysis showed a significant positive correlation of NLR with glycated hemoglobin (r=0.411), fasting plasma glucose (r=0.378), and HOMA-IR (r=0.233) (P<0.001). Regression analysis showed a linear increase in NLR with increasing severity of glucose intolerance even after adjusting for age, waist circumference, blood pressure, triglycerides, and smoking.

CONCLUSIONS

This is the first report on the correlation of NLR with different grades of glucose intolerance and insulin resistance. NLR can be used as an adjuvant prognostic marker for macro- and microvascular complications in patients with glucose intolerance.

Poly-ADP-ribose-polymerase inhibition ameliorates hind limb ischemia reperfusion injury in a murine model of type 2 diabetes

INTRODUCTION

Diabetes is known to increase poly-ADP-ribose-polymerase (PARP) activity and posttranslational poly-ADP-ribosylation of several regulatory proteins involved in inflammation and energy metabolism. These experiments test the hypothesis that PARP inhibition will modulate hind limb ischemia reperfusion (IR) in a mouse model of type-II diabetes and ameliorate the ribosylation and the activity/transnuclear localization of the key glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

METHODS

db/db mice underwent 1.5 hours of hind limb ischemia followed by 1, 7, or 24 hours of reperfusion. The treatment group received the PARP inhibitor PJ34 (PJ34) over a 24-hour period; the untreated group received Lactated Ringer (LR) at the same time points. IR muscles were analyzed for indices of PARP activity, fiber injury, metabolic activity, inflammation, GAPDH activity/intracellular localization, and poly-ADP-ribosylation of GAPDH.

RESULTS

PARP activity was significantly lower in the PJ34-treated groups than in the Lactated Ringer group at 7 and 24 hours of reperfusion. There was significantly less muscle fiber injury in the PJ34-treated group than in the Lactated Ringer-treated mice at 24 hours of reperfusion. PJ34 lowered levels of select proinflammatory molecules at 7 hours and 24 hours of IR. There were significant increases in metabolic activity only at 24 hours of IR in the PJ34 group, which temporally correlated with increase in GAPDH activity, decreased GAPDH poly-ADP-ribosylation, and nuclear translocation of GAPDH.

CONCLUSIONS

PJ34 reduced PARP activity, GAPDH ribosylation, and GAPDH translocation; ameliorated muscle fiber injury; and increased metabolic activity after hind limb IR injury in a murine model of type-II diabetes. PARP inhibition might be a therapeutic strategy after IR in diabetic humans.

Therapy for diabetic neuropathy: an overview

Neuropathy is a highly prevalent complication of diabetes that is only likely to increase as the diabetic epidemic continues. Unfortunately, the only disease-modifying treatment is to address the underlying diabetes with enhanced glucose control. In patients with type 1 diabetes, improved glycemic control dramatically reduces the incidence of neuropathy. In contrast, in patients with type 2 diabetes, better glucose control has only a marginal effect on the prevention of neuropathy. However, recognition and treatment of neuropathic pain is also important. An ever expanding number of randomized, controlled clinical trials support multiple medications for the reduction of pain. This includes medications such as calcium channel agonists, tricyclic antidepressants, and selective serotonin/norepinephrine reuptake inhibitors. However, the precise order and combination of these medications remains unclear. Furthermore, several new promising medications are being developed. Overall, the cornerstones of the treatment of diabetic neuropathy are improved glycemic control and initiation of a neuropathic pain medication with high levels of evidence to support its use when pain is present.

Therapeutic applications of PARP inhibitors: anticancer therapy and beyond

The aim of this article is to describe the current and potential clinical translation of pharmacological inhibitors of poly(ADP-ribose) polymerase (PARP) for the therapy of various diseases. The first section of the present review summarizes the available preclinical and clinical data with PARP inhibitors in various forms of cancer. In this context, the role of PARP in single-strand DNA break repair is relevant, leading to replication-associated lesions that cannot be repaired if homologous recombination repair (HRR) is defective, and the synthetic lethality of PARP inhibitors in HRR-defective cancer. HRR defects are classically associated with BRCA1 and 2 mutations associated with familial breast and ovarian cancer, but there may be many other causes of HRR defects. Thus, PARP inhibitors may be the drugs of choice for BRCA mutant breast and ovarian cancers, and extend beyond these tumors if appropriate biomarkers can be developed to identify HRR defects. Multiple lines of preclinical data demonstrate that PARP inhibition increases cytotoxicity and tumor growth delay in combination with temozolomide, topoisomerase inhibitors and ionizing radiation. Both single agent and combination clinical trials are underway. The final part of the first section of the present review summarizes the current status of the various PARP inhibitors that are in various stages of clinical development. The second section of the present review summarizes the role of PARP in selected non-oncologic indications. In a number of severe, acute diseases (such as stroke, neurotrauma, circulatory shock and acute myocardial infarction) the clinical translatability of PARP inhibition is supported by multiple lines of preclinical data, as well as observational data demonstrating PARP activation in human tissue samples. In these disease indications, PARP overactivation due to oxidative and nitrative stress drives cell necrosis and pro-inflammatory gene expression, which contributes to disease pathology. Accordingly, multiple lines of preclinical data indicate the efficacy of PARP inhibitors to preserve viable tissue and to down-regulate inflammatory responses. As the clinical trials with PARP inhibitors in various forms of cancer progress, it is hoped that a second line of clinical investigations, aimed at testing of PARP inhibitors for various non-oncologic indications, will be initiated, as well.

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.

Accelerated fat cell aging links oxidative stress and insulin resistance in adipocytes

Telomere shortening is emerging as a biological indicator of accelerated aging and aging-related diseases including type 2 diabetes. While telomere length measurements were largely done in white blood cells, there is lack of studies on telomere length in relation to oxidative stress in target tissues affected in diabetes. Therefore, the aim of this study is to induct oxidative stress in adipocytes and to test whether these adipocytes exhibit shortened telomeres, senescence and functional impairment. 3T3-L1 adipocytes were subjected to oxidative stress and senescence induction by a variety of means for 2 weeks (exogenous application of H2O2, glucose oxidase, asymmetric dimethylarginine (ADMA) and glucose oscillations). Cells were probed for reactive oxygen species generation (ROS), DNA damage, mRNA and protein expression of senescent and pro-inflammatory markers, telomere length and glucose uptake. Compared to untreated cells, both ROS generation and DNA damage were significantly higher in cells subjected to oxidative stress and senescence. Adipocytes subjected to oxidative stress also showed shortened telomeres and increased mRNA and protein expression of p53, p21, TNF alpha and IL-6. Senescent cells were also characterized by decreased levels of adiponectin and impaired glucose uptake. Briefly, adipocytes under oxidative stress exhibited increased ROS generation, DNA damage, shortened telomeres and switched to senescent/pro-inflammatory phenotype with impaired glucose uptake.

Evaluation of oxidative stress markers in pathogenesis of diabetic neuropathy

Experimental evidences suggest that hyperglycaemia-induced overproduction of reactive oxygen species and subsequent damage to proteins, lipids and DNA may play a key role in the development of distal symmetric polyneuropathy (DSPN)—the most common complication of diabetes mellitus. The study population consisted of 51 individuals aged 52–82 years classified into 3 groups: 16 patients diagnosed with type 2 diabetes mellitus (T2DM) with DSPN, 16 T2DM patients without DSPN and 19 control subjects without diabetes and neuropathy. The study was conducted to determine the activity of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and total antioxidant status (TAS) in the examined groups. An alkaline comet assay was used to determine the extent of DNA damage of oxidized purines as glicosylo-formamidoglicosylase (Fpg) sites, and oxidized pyrimidines as endonuclease III (Nth) sites. A significant decrease of SOD (P < 0.05), GPX (P < 0.05) and nonsignificant decrease of CAT (P > 0.05), and TAS status (P > 0.05) were seen in T2DM patients with neuropathy compared to T2DM patients as well as controls. T2DM patients with or without neuropathy revealed significantly lower (P < 0.05) plasma concentration of nitrous oxide compared to the control subjects. Endogenous level of oxidative DNA damage in T2DM patients with DSPN was significantly higher compared both to the controls and T2DM patients without DSPN (P < 0.001). Moreover, lymphocytes isolated from T2DM patients with DSPN were more susceptible to oxidative DNA lesions induced by hydrogen peroxide than from T2DM patients without DSPN (P < 0.001). Our results confirm hypothesis that oxidative stress may play a substantial role in the development and progression of diabetic distal symmetric polyneuropathy.

Amelioration of glucolipotoxicity-induced endoplasmic reticulum stress by a "chemical chaperone" in human THP-1 monocytes

Chronic ER stress is emerging as a trigger that imbalances a number of systemic and arterial-wall factors and promote atherosclerosis. Macrophage apoptosis within advanced atherosclerotic lesions is also known to increase the risk of atherothrombotic disease. We hypothesize that glucolipotoxicity might mediate monocyte activation and apoptosis through ER stress. Therefore, the aims of this study are (a) to investigate whether glucolipotoxicity could impose ER stress and apoptosis in THP-1 human monocytes and (b) to investigate whether 4-Phenyl butyric acid (PBA), a chemical chaperone could resist the glucolipotoxicity-induced ER stress and apoptosis. Cells subjected to either glucolipotoxicity or tunicamycin exhibited increased ROS generation, gene and protein (PERK, GRP-78, IRE1α, and CHOP) expression of ER stress markers. In addition, these cells showed increased TRPC-6 channel expression and apoptosis as revealed by DNA damage and increased caspase-3 activity. While glucolipotoxicity/tunicamycin increased oxidative stress, ER stress, mRNA expression of TRPC-6, and programmed the THP-1 monocytes towards apoptosis, all these molecular perturbations were resisted by PBA. Since ER stress is one of the underlying causes of monocyte dysfunction in diabetes and atherosclerosis, our study emphasize that chemical chaperones such as PBA could alleviate ER stress and have potential to become novel therapeutics.

Cellular dysfunction in diabetes as maladaptive response to mitochondrial oxidative stress

Oxidative stress has been implicated in diabetes long-term complications. In this paper, we summarize the growing evidence suggesting that hyperglycemia-induced overproduction of superoxide by mitochondrial electron transport chain triggers a maladaptive response by affecting several metabolic and signaling pathways involved in the pathophysiology of cellular dysfunction and diabetic complications. In particular, it is our goal to describe physiological mechanisms underlying the mitochondrial free radical production and regulation to explain the oxidative stress derived from a high intracellular glucose concentration and the resulting maladaptive response that leads to a cellular dysfunction and pathological state. Finally, we outline potential therapies for diabetes focused to the prevention of mitochondrial oxidative damage.

Role and clinical significance of lymphocyte mitochondrial dysfunction in type 2 diabetes mellitus

Lymphocyte homeostasis in type 2 diabetes mellitus (T2DM) is associated with increased susceptibility to infections. Mitochondrial oxidative stress is implicated primarily in the immune pathophysiology of diabetes; however, the molecular underpinnings of lymphocyte mitochondrial dysfunction and ensuing downstream cellular effects are hitherto unreported. Both in early diagnosed patients and patients with late complications, we observed an inverse correlation between mitochondrial DNA content in lymphocytes and hemoglobin A1 (HbA1c) levels. This relation established for the first time might serve as a general, yet direct, predictor or indicator for mitochondrial dysfunction in T2DM. Compared with controls, nuclear DNA damage response was higher (P ≤ 0.001) in diabetic subjects with increased accumulation of phospho-ataxia-telangiectasia (ATM), γ-H2AX, along with active recruitment of repair proteins (Mre11, Rad50, and Nbs1). A higher frequency (>2%) of stable chromosomal anomalies with loss of telomere integrity was observed in cases with late complications. A significant decrease (P ≤ 0.001) in enzyme activity of complex II, III, and IV of mitochondrial respiratory chain was evident in both diabetic groups in comparison with healthy controls. Activation in the cascade of nuclear factor kappa-beta (NF-κβ)-mediated feed-forward proinflammatory cytokine response was noted among T2DM subjects. Increased oxidative stress, mitochondrial membrane depolarization, activation of caspase-3, and PARP observed in diabetic groups indicated bax triggered mitochondrial mediated cellular apoptosis. Our results provide the first insights of lymphocyte mitochondrial dysfunction that might be helpful in explaining the clinical significance of immunologic perturbation observed in type 2 diabetic conditions. Our data also indicate that maneuvering through the mitochondrial function might be a viable, indirect method to modulate lymphocyte homeostasis in T2DM.

Alkaline, Endo III and FPG modified comet assay as biomarkers for the detection of oxidative DNA damage in rats with experimentally induced diabetes

Increased production of reactive oxygen species under diabetic condition underlines the higher oxidatively damaged DNA in different tissues. However, it is practically difficult to assess the oxidatively damaged DNA in different internal organs. Therefore, the present study was aimed to evaluate the extent of oxidative stress-induced DNA damage in different organs with the progression of diabetes. Diabetic and control Sprague Dawley rats were sacrificed in time-dependent manner and the lung, liver, heart, aorta, kidney, pancreas and peripheral blood lymphocytes (PBL) were analyzed for both alkaline and modified comet assay with endonuclease-III (Endo III) and formamidopyrimidine-DNA glycosylase (FPG) (hereafter called modified comet assay) for the detection of oxidative DNA damage. The statistically significant increase in olive tail moment (OTM) was found in all the tested tissues. The extent of DNA damage was increased with the progression of diabetes as revealed by the parameter of OTM in alkaline and modified comet assay. Further, the positive correlations were observed between OTM of the lung, liver, heart, aorta, kidney and pancreas with PBL of diabetic rat in the alkaline and modified comet assay. Moreover, significant increase in the 8-oxodG positive nuclei in the lung, liver, heart, aorta, kidney and pancreas was observed in 4th and 8th week diabetic rat as compared to control. Results of the present study clearly indicated the suitability of alkaline and modified comet assay for the detection of multi-organ oxidative DNA damage in streptozotocin (STZ)-induced diabetic rat and showed that damaged DNA of PBL can be used as a suitable biomarker to assess the internal organs response to DNA damage in diabetes.

Signaling mechanism of poly(ADP-ribose) polymerase-1 (PARP-1) in inflammatory diseases

Poly(ADP-ribosyl)ation, attaching the ADP-ribose polymer chain to the receptor protein, is a unique posttranslational modification. Poly(ADP-ribose) polymerase-1 (PARP-1) is a well-characterized member of the PARP family. In this review, we provide a general update on molecular structure and structure-based activity of this enzyme. However, we mainly focus on the roles of PARP-1 in inflammatory diseases. Specifically, we discuss the signaling pathway context that PARP-1 is involved in to regulate the pathogenesis of inflammation. PARP-1 facilitates diverse inflammatory responses by promoting inflammation-relevant gene expression, such as cytokines, oxidation-reduction-related enzymes, and adhesion molecules. Excessive activation of PARP-1 induces mitochondria-associated cell death in injured tissues and constitutes another mechanism for exacerbating inflammation.

Impaired miR-146a expression links subclinical inflammation and insulin resistance in Type 2 diabetes

Type 2 diabetes patients exhibit subclinical inflammation but the regulatory mechanisms are poorly understood. We sought to evaluate the role of miR-146a expression along with its downstream proinflammatory signals in relation to glycemic control and insulin resistance. Study subjects (n = 20 each) comprised of clinically well characterized Type 2 diabetes patients and control non-diabetic subjects. miRNA and mRNA expression levels were probed in peripheral blood mononuclear cells (PBMC) by Real-time RT-PCR and plasma levels of TNFα and IL-6 were measured by ELISA. The miR-146a expression levels were significantly decreased in PBMCs from patients with Type 2 diabetes compared to control subjects. Among the target genes of miR-146a, TRAF-6 mRNA expression was significantly increased in patients with Type 2 diabetes while there was no significant difference in the mRNA levels of IRAK1 in the study groups. In contrast, there were significantly increased levels of NFκB expression in patients with Type 2 diabetes. There was an increased trend in the levels of TNFα and IL-6 mRNA in patients with type 2 diabetes. While SOCS-3 mRNA levels increased, plasma TNFα and IL-6 levels were also significantly higher in patients with type 2 diabetes. miR-146a expression was negatively correlated to glycated hemoglobin, insulin resistance, TRAF6, and NFκB mRNA levels and circulatory levels of TNFα and IL-6. Reduced miR-146a levels are associated with insulin resistance, poor glycemic control, and several proinflammatory cytokine genes and circulatory levels of TNFα and IL-6 in Asian Indian Type 2 diabetic patients.

Biomarkers of oxidative stress: methods and measures of oxidative DNA damage (COMET assay) and telomere shortening

Oxidative stress is fast becoming the nutritional and medical buzzword for the twenty-first century. The theoretical importance of oxidative stress in diabetes is highlighted by its potential double impact on metabolic dysfunction on one hand and the vascular system on the other hand. The new concept of oxidative stress, being an important trigger in the onset and progression of diabetes and its complications, emphasizes the need for measurement of markers of oxidation to assess the degree of oxidative stress. While we have been routinely measuring biomarkers in our molecular epidemiology projects, here we discuss the utility of two assays, (a) DNA damage assessment by COMET measurement and (b) telomere length measurement. As DNA damage is efficiently repaired by cellular enzymes, its measurement gives a snapshot view of the level of oxidative stress. The protocol allows for measurement of oxidative DNA damage (FPG-sensitive DNA strand breaks). Telomere length measured by Southern blotting technique allows one to estimate the chronic burden of oxidative stress at the molecular level and is now considered as biomarker of biological aging.

Molecular biological effects of selective neuronal nitric oxide synthase inhibition in ovine lung injury

Neuronal nitric oxide synthase is critically involved in the pathogenesis of acute lung injury resulting from combined burn and smoke inhalation injury. We hypothesized that 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, blocks central molecular mechanisms involved in the pathophysiology of this double-hit insult. Twenty-five adult ewes were surgically prepared and randomly allocated to 1) an uninjured, untreated sham group (n = 7), 2) an injured control group with no treatment (n = 7), 3) an injury group treated with 7-nitroindazole from 1-h postinjury to the remainder of the 24-h study period (n = 7), or 4) a sham-operated group subjected only to 7-nitroindazole to judge the effects in health. The combination injury was associated with twofold increased activity of neuronal nitric oxide synthase and oxidative/nitrosative stress, as indicated by significant increases in plasma nitrate/nitrite concentrations, 3-nitrotyrosine (an indicator of peroxynitrite formation), and malondialdehyde lung tissue content. The presence of systemic inflammation was evidenced by twofold, sixfold, and threefold increases in poly(ADP-ribose) polymerase, IL-8, and myeloperoxidase lung tissue concentrations, respectively (each P < 0.05 vs. sham). These molecular changes were linked to tissue damage, airway obstruction, and pulmonary shunting with deteriorated gas exchange. 7-Nitroindazole blocked, or at least attenuated, all these pathological changes. Our findings suggest 1) that nitric oxide formation derived from increased neuronal nitric oxide synthase activity represents a pivotal reactive agent in the patho-physiology of combined burn and smoke inhalation injury and 2) that selective neuronal nitric oxide synthase inhibition represents a goal-directed approach to attenuate the degree of injury.

c-Jun NH2-terminal kinase activity in subcutaneous adipose tissue but not nuclear factor-kappaB activity in peripheral blood mononuclear cells is an independent determinant of insulin resistance in healthy individuals

OBJECTIVE

Chronic low-grade activation of the immune system (CLAIS) predicts type 2 diabetes via a decrease in insulin sensitivity. Our study investigated potential relationships between nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK) pathways-two pathways proposed as the link between CLAIS and insulin resistance.

RESEARCH DESIGN AND METHODS

Adiposity (dual-energy X-ray absorptiometry), waist-to-hip ratio (WHR), and insulin sensitivity (M, hyperinsulinemic-euglycemic clamp) were measured in 22 healthy nondiabetic volunteers (aged 29 +/- 11 years, body fat 28 +/- 11%). NF-kappaB activity (DNA-binding assay) and JNK1/2 activity (phosphorylated JNK) were assessed in biopsies of the vastus lateralis muscle and subcutaneous adipose tissue and in peripheral blood mononuclear cell (PBMC) lysates.

RESULTS

NF-kappaB activities in PBMCs and muscle were positively associated with WHR after adjustment for age, sex, and percent body fat (both P < 0.05). NF-kappaB activity in PBMCs was inversely associated with M after adjustment for age, sex, percent body fat, and WHR (P = 0.02) and explained 16% of the variance of M. There were no significant relationships between NF-kappaB activity and M in muscle or adipose tissue (both NS). Adipose-derived JNK1/2 activity was not associated with obesity (all P> 0.1), although it was inversely related to M (r = -0.54, P < 0.05) and explained 29% of its variance. When both NF-kappaB and JNK1/2 were examined statistically, only JNK1/2 activity in adipose tissue was a significant determinant of insulin resistance (P = 0.02).

CONCLUSIONS

JNK1/2 activity in adipose tissue but not NF-kappaB activity in PBMCs is an independent determinant of insulin resistance in healthy individuals.