Serum and urinary nitrites and nitrates and Doppler sonography in children with diabetes

Exploring the Molecular Modalities in the Pathogenesis of Diabetic Kidney Disease with a Focus on the Potential Therapeutic Implications

Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease (CKD) and end-stage renal disease worldwide, affecting approximately 40% of individuals with type 2 diabetes (T2DM) and 30% of those with type 1 diabetes (T1DM). As the prevalence of diabetes continues to rise, the burden of DKD is expected to grow correspondingly. This review explores the roles of key molecular pathways, including the apelinergic system, vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) axis, and nitric oxide (NO)/nitric oxide synthase (NOS) signaling, in DKD pathogenesis and potential therapeutic applications. The apelinergic system, involving apelin and its receptor (APLNR), influences endothelial function, glucose metabolism, and renal health. Preclinical studies highlight its dual role in renal protection and injury through anti-inflammatory and antioxidant pathways, while other evidence suggests that it may exacerbate DKD through podocyte damage and angiogenesis. Similarly, the VEGF/VEGFR axis demonstrates a complex contribution to DKD, where VEGF-A promotes pathological angiogenesis and glomerular damage, but its inhibition requires careful modulation to prevent adverse effects. The NO/NOS system, integral to vascular and renal homeostasis, also exhibits altered activity in DKD, with reduced bioavailability linked to oxidative stress and inflammation. This review underscores the intricate interplay between these pathways in DKD, revealing both challenges and opportunities in their therapeutic targeting. Further research is essential to refine strategies and develop effective interventions for DKD management.

Cystatin C, renal resistance index, and kidney injury molecule-1 are potential early predictors of diabetic kidney disease in children with type 1 diabetes

BACKGROUND

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease in patients with diabetes mellitus type I (DM-T1). Microalbuminuria and estimated glomerular filtration rate (eGFR) are standard predictors of DKD. However, these predictors have serious weaknesses. Our study aimed to analyze cystatin C, renal resistance index, and urinary kidney injury molecule-1 (KIM-1) as predictors of DKD.

METHODS

We conducted a cross-sectional study in 2019 on a consecutive sample of children and adolescents (10-18 years) diagnosed with DM-T1. The outcome was a risk for DKD estimated using standard predictors: age, urinary albumin, eGFR, serum creatinine, DM-T1 duration, HbA1c, blood pressure, and body mass index (BMI). We conducted the analysis using structural equation modeling.

RESULTS

We enrolled 75 children, 36 girls and 39 boys with the median interquartile range (IQR) age of 14 (11-16) years and a median (IQR) duration of DM-T1 of 6 (4-9) years. The three focal predictors (cystatin C, resistance index, and urinary KIM-1) were significantly associated with the estimated risk for DKD. Raw path coefficients for cystatin C were 3.16 [95% CI 0.78; 5.53; p = 0.009, false discovery rate (FDR) < 5%], for renal resistance index were -8.14 (95% CI -15.36; -0.92; p = 0.027; FDR < 5%), and for urinary KIM-1 were 0.47 (95% CI 0.02; 0.93; p = 0.040; FDR < 5%).

CONCLUSION

Cystatin C, renal resistance index, and KIM-1 may be associated with the risk for DKD in children and adolescents diagnosed with DM-T1. We encourage further prospective cohort studies to test our results.

Differences in serum markers of oxidative stress in well controlled and poorly controlled asthma in Sri Lankan children: a pilot study

Background

Asthma is a disease characterised by hyper responsiveness and bronchoconstriction of airways, and is a major health burden globally. A dysfunction of the oxidant-antioxidant balance, termed oxidative stress, has been implicated in the pathophysiology of asthma. The present study aims to assess the changes in oxidative stress markers, namely nitric oxide metabolites and antioxidant capacity, in children with poorly controlled and well controlled asthma, in comparison to healthy controls.

Methods

The present study enrolled 72 children (ages 5-15 years) classified into three groups: (1) poorly controlled asthma (n = 20), (2) well controlled asthma (n = 24) and (3) healthy controls (n = 27). An interviewer-administered questionnaire was used to record socio-demographic data of the participants. The serum concentrations of the oxidant markers (nitrite, nitrate and total nitric oxide metabolites [NO_x]) were determined using the Griess test, and the total antioxidant capacity (TAOC) was determined using the ABTS decolorisation method. The concentrations of these markers were compared across the three groups.

Results

The three study groups were similar in terms of socio-demographic data. The differences across the three groups were statistically significant for serum concentrations of nitrate and NO_x (but not nitrite) and serum TAOC. Further analyses showed that the disparity for nitrate and NO_x concentrations was greatest between poorly controlled asthma and healthy controls (p = 0.001 and p < 0.001) compared to the well-controlled asthmatics and healthy controls (p = 0.036 and p = 0.049). A significant difference in serum nitrate and NO_x concentrations was not observed between the two asthma groups (p = 0.311 and 0.203). The TAOC were significantly lower in poorly controlled asthmatics as compared to well-controlled asthmatics (p = 0.003) and healthy controls (p < 0.001). However, there was no significant difference in the serum TAOC between healthy controls and well-controlled asthmatics (p = 0.496). These findings may indicate that it is perhaps the higher TAOC that contributes to the well controlled state of asthma.

Conclusions

The present study indicated that an imbalance of oxidants and antioxidants in the serum may have an underlying role in asthma pathophysiology, and how these markers may be effective in asthma management.

Nitric oxide metabolism is impaired by type 1 diabetes and diabetic nephropathy

Diabetes leads to reduced nitric oxide bioavailability, resulting in endothelial dysfunction. However, overproduction of nitric oxide due to hyperglycaemia is associated with oxidative stress and tissue damage. The objective of this study was to characterise nitric oxide production (NO) and added nitrite and nitrate (NO₂ ^-+NO₃ ^-) concentration in the blood and urine of patients with and without diabetic nephropathy. A total of 268 patients with type 1 diabetes and 69 healthy subjects were included. Diabetic nephropathy was defined as macroalbuminuria and/or estimated glomerular filtration rate below 60 ml/min/1.73 cm². NO₂ ^-+NO₃ ^- concentration was measured by Griess reaction. Production of NO was detected by electron paramagnetic resonance spectroscopy. Blood NO was demonstrated to be higher (P<0.001) and serum NO₂ ^-+NO₃ ^- was lower (P=0.003) in patients with type 1 diabetes and no nephropathy vs. healthy subjects. However, serum NO₂ ^-+NO₃ ^- concentration in patients with diabetes and nephropathy did not differ from the levels observed in healthy controls. Urine excretion of NO₂ ^-+NO₃ ^- was significantly decreased in patients with nephropathy, compared with patients without diabetic kidney disease (P=0.006) and healthy subjects (P=0.010). A significant positive correlation was observed between urine NO₂ ^-+NO₃ ^- and estimated glomerular filtration rate in patients with type 1 diabetes (P=0.002) and healthy subjects (P=0.008). Estimated glomerular filtration rate, albuminuria and diabetic nephropathy status were significant predictors of the whole blood NO and NO₂ ^-+NO₃ ^- in serum and urine in patients with type 1 diabetes, as identified by linear regression models. The present study concludes that NO metabolism is impaired by type 1 diabetes and diabetic nephropathy.

The renal resistive index as a new complementary tool to predict microvascular diabetic complications in children and adolescents: a groundbreaking finding

The increasing prevalence of type 1 diabetes mellitus (DM) has made it necessary to have new markers for early detection of diabetic nephropathy. Renal resistive index (RI) by using renal Doppler can be a helpful tool in detecting functional alterations in renal hemodynamics. This study was conducted on 100 children and adolescents with type 1 DM. They were further subdivided into two equal subgroups: group 1 with type 1 DM and normo-albuminuria [urinary albumin excretion (UAE) <30 mg/24 hours], and group 2 with type 1 DM and hyper-albuminuria (increased UAE >30 mg/24 hours). There were 37 males (37%) and 63 females (63%); their mean ages were 13.6±2.53 (range, 10-19) years and mean disease duration was 8.867±2.260 (range, 5-13) years. Progressive increase in RI was significantly associated with increased disease duration more than 10 years, elevated serum HbA1c more than 7.5% and early pubertal stages. While not significantly related to sex, weight, height, blood pressure or serum lipid profile, diabetic micro-vascular complications (nephropathy and sensory neuropathy) were more prevalent among patients with RI more than 0.58. Renal RI could be a useful complementary test for the evaluation of functional alterations in renal hemodynamics in the early stages of diabetic nephropathy.

Renal resistive index significantly increased in hypertensive children and it is independently related to the pulse pressure and left ventricular mass index

Background: To the best our knowledge there is no data in the literature related to changes in renal resistive index (RRI) values in children who have hypertension (HT). In this study, we aimed to investigate the changes of RRI values and it is usability in children with HT. Methods: A total of 75 children; 48 with newly diagnosed HT and 27 healthy controls were included in the study. Routine history, physical examination, and laboratory examinations were performed. Left ventricular (LV) dimensions and systolic-diastolic functions, septum and posterior wall thickness (IVSd and PWd) and LV mass index (LVMI) were calculated by echocardiography. In addition to routine renal ultrasonography (US), renal pulsatility indexes (RPI), accelerated time and RRI were measured. Increased RRI was accepted as >0.70. Results: Increased RRI was detected in 25 (52%) of HT patients. Systolic and diastolic blood pressure (SBP and DBP), and pulse pressure (PP), low-density lipoprotein cholesterol and triglyceride levels, RRI, RPI, kidney length, IVSd, PWd, and LVMI were significantly higher in patients with HT (both p < 0.05). SBP and PP, PWd, LV ejection fraction, LV fractional shortening, and LVMI were positively correlated with the RRI. High-density lipoprotein cholesterol was negatively correlated with the RRI. Of these measurements, RRI values were found to be independently associated with PP and LVMI (p < 0.05). Conclusions: In hypertensive children, RRI was significantly higher than healthy controls and it is also related with LVMI and PP.

Follow Up of Value of the Intrarenal Resistivity Indices and Different Renal Biomarkers for Early Identification of Diabetic Nephropathy in Type 1 Diabetic Patients

AIM

To evaluate intrarenal resistivity index (RI) and different biomarkers of diabetic nephropathy (DN) with clinical signs of DN and its progression over time as early detection of DN.

PATIENTS AND METHODS

This longitudinal study included 48 type 1 diabetic patients who were studied at baseline and after three years. A blood sample was taken for assessment of glycosylated haemoglobin (HbA1), lipid profile and a urine sample was taken for assessment of albumin/creatinine ratio, Neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP) and kidney injury molecule-1 (Kim-1) at baseline and after three years. Forty diabetic patients did renal Doppler at baseline & after three years.

RESULTS

HbA1, waist/hip ratio, albumin/creatinine ratio, lipid profile, NGAL, KIM-1, L-FABP and resistivity index (RI) were significantly increased in follow-up. Twenty patients (41.7%) showed progression to albuminuria. RI showed a significant increase in follow-up study. ROC curve showed that RI and NGAL had the highest sensitivity (100%), followed by L-FABP (90%) and lastly KIM-1 (63.6%) in the prediction of DN.

CONCLUSION

High RI, NGAL, KIM-1 & L-FABP can be considered as early markers of diabetic nephropathy in type 1 diabetics and are associated with its progression over time, independent of albuminuria.

Effects of linagliptin on renal endothelial function in patients with type 2 diabetes: a randomised clinical trial

AIMS/HYPOTHESIS

Endothelial dysfunction predicts cardiovascular damage and renal involvement. Animal experiments and human studies indicate an increased nitric oxide (NO) activity and endothelial NO synthase (NOS) expression in the early stage of type 2 diabetes. The aim of the study was to assess the effect of linagliptin on the endothelial function of the renal vasculature.

METHODS

In this randomised, double-blind, parallel-group, investigator-initiated trial, 62 patients with type 2 diabetes were randomly assigned (by computer-generated random code) to receive linagliptin 5 mg (n = 30) or placebo (n = 32) for 4 weeks. The primary objective was to assess endothelial function of the renal vasculature, by constant-infusion input-clearance and urinary albumin/creatinine ratio (UACR), both before and after blockade of NOS with N ^G-monomethyl-L-arginine (L-NMMA).

RESULTS

Treatment with linagliptin for 4 weeks reduced fasting, postprandial blood glucose and HbA_1c, although not significantly; no change occurred with placebo. Renal plasma flow (RPF) did not change after linagliptin or placebo. After 4 weeks the absolute change in RPF due to L-NMMA was smaller in the linagliptin group than in the placebo group (-46.8 ± 34 vs -65.1 ± 36 ml/min, p = 0.045), indicating a lower basal NO activity after treatment with linagliptin. Consistently, the response of UACR to L-NMMA increased in the placebo group (p = 0.059) but not in the linagliptin group (p = 0.276), pointing to an upregulation of NO activity in the placebo group. No clinically meaningful safety concerns were evident.

CONCLUSIONS/INTERPRETATION

Our data suggest that treatment with the dipeptidyl peptidase-4 inhibitor linagliptin for 4 weeks prevented the impairment of renal endothelial function due to hyperglycaemia in type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01835678 FUNDING: : This study was funded by Boehringer Ingelheim.

1,25-dihydroxyvitamin D3 down-modulates the production of proinflammatory cytokines and nitric oxide and enhances the phosphorylation of monocyte-expressed STAT6 at the recent-onset type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is associated with an imbalance between inflammation and repair. Recently, the biologically active form of vitamin D₃, i.e. 1,25(OH)₂D₃, has been reported to have potent immunomodulatory effects on both innate and adaptive immune cells, as well as on the production of their specific cytokines.

METHODS

We examined the effect of 1,25(OH)₂D₃ on the production of proinflammatory Th1/Th17 and anti-inflammatory Th2/Treg related cytokines, as well as on the phosphorylation of monocyte-expressed STAT4 and STAT6 at the recent-onset human T1D.

RESULTS

The levels of IFN-γ, IL-17 and nitric oxide (NO) production were significantly increased in peripheral blood mononuclear cells (PBMCs) from patients with T1D compared to controls. Similarly, STAT4 tyrosine phosphorylation (p-STAT4, Tyr693) levels were significantly increased in monocytes from patients when compared to controls. Conversely, the levels of IL-4, IL-10 and p-STAT6 (Tyr641) were significantly decreased in type 1 diabetic patients than in controls. Treatment with 1,25(OH)₂D₃ resulted in significant up-regulation of IL-4, IL-10, arginase activity, and p-STAT6 and, conversely, down-regulation of IFN-γ, IL-17 and NO production levels, as well as p-STAT4. Additionally, 1,25(OH)₂D₃ significantly enhanced Treg-to-Th17 ratio, and induced a significant decrease in Th1-to-Th2, NO production-to-arginase activity and p-STAT4-to-p-STAT6 ratios.

CONCLUSIONS

Our study suggests that the biologically active form of vitamin D can reverse the activation of inflammatory pathways at the onset of T1D. Additionally, its immunomodulation properties may vary depending on the overall patterns of cytokines. From a therapeutic point of view, vitamin D may potentially be suggested as an immunological adjuvant and a potential anti-inflammatory agent in individuals at risk of T1D.

Nitric oxide levels in patients with diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Altered serum nitric oxide (NO) levels in patients with diabetes mellitus (DM) have been reported by different studies; however, results are still controversial. Until this date, no meta-analysis evaluated the association of NO levels with DM. Thus, this paper describes a meta-analysis conducted to evaluate if there is a relationship between NO levels and type 1 DM (T1DM) or type 2 DM (T2DM).

METHODS

A literature search was done to identify all studies that investigated NO levels between T1DM or T2DM patients (cases) and non-diabetic subjects (controls). Measurement of nitrate and nitrite (NOx - the stable NO products) were used to estimate NO concentrations because they closely reflect NO bioavailability. Weighted mean differences (WMD) of NOx levels between case and control samples were calculated for T1DM and T2DM groups.

RESULTS

Thirty studies were eligible for inclusion in the meta-analysis (8 in T1DM samples and 22 in T2DM samples). NOx levels were increased in European T1DM patients compared with controls [random effect model (REM) WMD = 8.55, 95% CI 2.88 - 14.21]. No other ethnicity was evaluated in T1DM studies. NOx levels were also increased in both European (REM WMD = 18.76, 95% CI 1.67 - 35.85) and Asian (REM WMD = 18.41, 95% CI 8.01 - 28.81) T2DM patients, but not in Latin American patients compared with controls.

CONCLUSIONS

This meta-analysis detected a significant increase in NOx levels in European T1DM patients as well as European and Asian T2DM patients. Further studies in other ethnicities are necessary to confirm these data.

Oxidative stress and nitric oxide are increased in obese children and correlate with cardiometabolic risk and renal function

Oxidative stress and nitric oxide (NO) appear to represent important links between obesity and cardiovascular, metabolic and/or renal disease. We investigated whether oxidative stress and NO production/metabolism are increased in overweight and obese prepubertal children and correlate with cardiometabolic risk and renal function. We performed a cross-sectional evaluation of 313 children aged 8-9 years. Anthropometrics, 24-h ambulatory blood pressure, pulse wave velocity (PWV), insulin resistance (homoeostasis model assessment index (HOMA-IR)), inflammatory/metabolic biomarkers, estimated glomerular filtration rate (eGFR), plasma total antioxidant status (TAS), plasma and urinary isoprostanes (P-Isop, U-Isop), urinary hydrogen peroxide (U-H2O2), and plasma and urinary nitrates and nitrites (P-NOx, U-NOx) were compared among normal weight, overweight and obese groups, according to WHO BMI z-score reference. U-Isop were increased in the obese group, whereas U-NOx were increased in both overweight and obese children. U-Isop were positively correlated with U-H2O2, myeloperoxidase (MPO), high-sensitivity C-reactive protein, HOMA-IR and TAG. TAS correlated negatively with U-Isop and MPO and positively with PWV. HOMA-IR and U-H2O2 were associated with higher U-Isop, independently of BMI and eGFR, and total cholesterol and U-H2O2 were associated with U-NOx, independently of BMI, eGFR values and P-NOx concentration. In overweight and obese children, eGFR decreased across P-NOx tertiles (median: 139·3 (25th, 75th percentile 128·0, 146·5), 128·0 (25th, 75th percentile 121·5, 140·4), 129·5 (25th, 75th percentile 119·4, 138·3), P for linear trend=0·003). We conclude that oxidant status and NO are increased in relation to fat accumulation and, even in young children, they translate into higher values of cardiometabolic risk markers and affect renal function.

Value of the intrarenal arterial resistivity indices and different renal biomarkers for early identification of diabetic nephropathy in type 1 diabetic patients

BACKGROUND

The aim of this study was to compare resistivity index (RI) in type 1 diabetic patients and normal controls and to evaluate whether high RI is associated with different biomarkers of diabetic nephropathy (DN) as early detection of DN offers the best chance of delaying or possibly preventing progression to end-stage renal disease.

METHODS

The study included 62 type 1 diabetic patients and 30 healthy volunteers of the same age and sex. Blood samples were taken for assessment of glycosylated hemoglobin, lipid profile and urine samples were taken for assessment of albumin/creatinine ratio, neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP) and kidney injury molecule-1 (Kim-1). Forty-five diabetic patients and 30 controls had a renal Doppler ultrasonography. t-Test or Mann Whitney U-test for independent variables, Pearson's or Spearman correlation analysis were used.

RESULTS

The mean age of diabetic patients was 16.3±1.5 years, and mean duration of diabetes was 9.4±2.9 years. RI, albumin/creatinine ratio, NGAL, Kim-1 and L-FABP were significantly higher in diabetics than in controls. RI, NGAL, Kim-1, and L-FABP were significantly higher in microalbuminuric compared to normoalbuminuric diabetics. In normoalbuminuric diabetics, RI, NGAL, Kim-1 and L-FABP were significantly higher compared to controls. The study revealed significant positive correlation between the RI in diabetics and both KIM-1 and albumin/creatinine ratio.

CONCLUSIONS

Increased RI and renal biomarkers in diabetics are early sensitive specific markers of DN, even preceded the development of microalbuminuria, denoting that they can be used as an early and sensitive markers for early detection of DN.

New 1,4-Dihydropyridines Down-regulate Nitric Oxide in Animals with Streptozotocin-induced Diabetes Mellitus and Protect Deoxyribonucleic Acid against Peroxynitrite Action

Diabetes mellitus (DM) and its complications cause numerous health and social problems throughout the world. Pathogenic actions of nitric oxide (NO) are responsible to a large extent for development of complications of DM. Search for compounds regulating NO production in patients with DM is thus important for the development of pharmacological drugs. Dihydropyridines (1,4-DHPs) are prospective compounds from this point of view. The goals of this study were to study the in vivo effects of new DHPs on NO and reactive nitrogen and oxygen species production in a streptozotocin (STZ)-induced model of DM in rats and to study their ability to protect DNA against nocive action of peroxynitrite. STZ-induced diabetes caused an increase in NO production in the liver, kidneys, blood and muscles, but a decrease in NO in adipose tissue of STZ-treated animals. Cerebrocrast treatment was followed by normalization of NO production in the liver, kidneys and blood. Two other DHPs, etaftorone and fenoftorone, were effective in decreasing NO production in kidneys, blood and muscles of diabetic animals. Furthermore, inhibitors of nitric oxide synthase (NOS) and an inhibitor of xanthine oxidoreductase (XOR) decreased NO production in kidneys of diabetic animals. Treatment with etaftorone decreased expression of inducible NOS and XOR in kidneys, whereas it increased the expression of endothelial NOS. In vitro, the studied DHPs did not significantly inhibit the activities of NOS and XOR but affected the reactivity of peroxynitrite with DNA. These new DHPs thus appear of strong interest for treatment of DM complications.

Characteristics of pediatric diabetic ketoacidosis patients in Saudi Arabia

OBJECTIVES

To evaluate the clinical and biochemical characteristics of children with diabetic ketoacidosis (DKA).

METHODS

In this retrospective study conducted between June 2012 and November 2013 at the King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia, we evaluated pediatric DKA admissions from 1995-2008 (Phase 1). From the case files, we obtained information related to patients' age, gender, weight, presenting complaints, serum biochemical profile, and management.

RESULTS

This study included 373 DKA admissions with a median age of 11 years (interquartile range [IQR]: 8-13). The patients in the subgroup of age more than 10 years old had the highest proportion of admissions (n=250, 67%, p&lt;0.000). The median duration of diagnosis of diabetes mellitus (DM) was 3 years (IQR: 2-6). New-onset DM was 47%. Predominant precipitating cause was acute illness, mostly viral syndrome in 22% of all cases, and non-compliance to insulin regimen was in 79% of  the diagnosed diabetic cases. Blood glucose, pH, anion gap, serum osmolality, serum potassium, and serum phosphate showed the highest change during the initial 6 hours of management, while trends of serum bicarbonate and blood urea nitrogen demonstrated a predominant change in the initial 12 hours.

CONCLUSION

The notable findings in this study, such as, higher mean age of presentation, high rate of non-compliance to insulin as the cause of precipitation, and a high prevalence of abdominal pain at presentation should be followed up with further comparative studies.

Hyperglycemia as a Risk Factor of Ischemic Stroke

Diabetes is considered a major risk factor for stroke and is associated with worsened stroke outcomes. Here, we discuss and summarize the mechanisms that have been associated with the increased risk of stroke due to the hyperglycemia in diabetes mellitus. In diabetic stroke models, hyperglycemia exaggerates the following damaging processes: acidosis, accumulation of reactive oxygen species/reactive nitrogen, inflammation and mitochondrial dysfunction. Understanding the mechanism of diabetes acting as a stroke risk factor will definitely assist to reveal issues related to drug metabolism and toxicity in diabetic stroke. In addition, it is suggested that future studies may focus on the mechanisms mediating blood-brain barrier and astrocytes dysfunction under hyperglycemic stroke.

Unbalanced oxidant-antioxidant status and its effects in pediatric diseases

Oxidative stress results from a disparity between the generation of reactive oxygen species and the antioxidant ability of the organism. The alteration of the oxidant-antioxidant system brings in adults an effective state of imbalance, which may influence the pathogenesis of many diseases. Oxidative stress also plays a pivotal role in the progression of various pathologies in childhood, through a manipulation of regulatory proteins. In fact, several studies have demonstrated that an unbalanced oxidant-antioxidant status is able to determine toxic effects even during infancy. Therefore, the aim of this review was to summarize current knowledge about the dynamic relationship between oxidative stress and systemic diseases during childhood. In order to better understand these complex mechanisms, a comprehensive review of the literature was done, focusing mainly on pre-pubertal children. In fact, this age-group offers a unique opportunity to exclude confounding factors, especially those related to the metabolic effects induced by puberty. Early identification of these very young patients should be aimed at minimizing the degree of oxidative damage. Only by achieving early diagnosis, will it be possible to identify those children who could benefit from specific therapeutic approaches targeting oxidative stress.

Renal Doppler indices in diabetic children with insulin resistance syndrome

End-stage renal failure is still a leading cause of mortality among type 1 diabetes patients. Insulin resistance plays a larger role in type 1 diabetes disease process than is commonly recognized. Detection of diabetic nephropathy as early as possible currently offers the best chance of delaying or possibly preventing progression to end-stage disease. Renal resistive index (RI) and pulsatility index (PI), measured using renal Doppler ultrasonography, reflect intrarenal vascular resistance. The present work aimed at examining renal Doppler indices (RI and PI) in type 1 diabetic children and their relation to features of insulin resistance and other established parameters of early diabetic nephropathy as microalbuminuria. One hundred diabetic children with a mean age of 13.4 ± 2.9 yr and an average diabetes duration of (7.2 ± 2.5 yr) were included. Thirty healthy children served as controls. All renal Doppler indices were significantly higher in children with type 1 diabetes mellitus (p ≤ 0.01). The worst parameters were observed in children diagnosed with insulin resistance syndrome (IRS) (38%), hypertensive (12%), and obese (4%) children. Resistive index showed a significant correlation to blood pressure (r = 0.2, p = 0.04), waist-hip ratio (r = 0.5, p = 0.02), insulin dose (r = 0.2, p = 0.02) and estimated glucose disposal rate (r = -0.5, p = 0.01). No correlation was noted to microalbuminuria, HbA1c, or duration of diabetes. The present work concluded that renal Doppler indices are worse in diabetic children and particularly those with IRS. These children appear to be at graver risk for diabetic nephropathy. In these patients adding renal Doppler assessment to their work up, might diagnose diabetic nephropathy at a prealbuminuric stage.

Urinary biomarkers involved in type 2 diabetes: a review

Diabetes mellitus is one of the most challenging health concerns of the 21st century. With at least 30% of the diabetic population remaining undiagnosed, effective and early diagnosis is of critical concern. Development of a diagnostic test, more convenient and reliable than those currently used, would therefore be highly beneficial. Urine as a diagnostic medium allows for non-invasive detection of biomarkers, including some associated with type 2 diabetes and its complications. This review provides a synopsis of those urinary biomarkers that potentially may provide a basis for the development of improved diagnostic tests. Three main pathways for the sourcing of potential makers are identified: kidney damage, oxidative stress and low-grade inflammation including atherosclerosis/vascular damage. This review briefly presents each pathway and some of the most relevant urinary biomarkers that may be used to monitor the development or progression of diabetes and its complications. In particular, biomarkers of renal dysfunction such as transferrin, type IV collagen and N-acetyl-beta-D-glucosaminidase might prove to be more sensitive than urinary albumin, the current gold standard, in the detection of incipient nephropathy and risk assessment of cardiovascular disease. Inflammatory markers including orosomucoid, tumour necrosis factor-alpha, transforming growth factor-beta, vascular endothelial growth factor and monocyte chemoattractant protein-1, as well as oxidative stress markers such as 8-hydroxy-2'deoxyguanosine may also be useful biomarkers for diagnosis or monitoring of diabetic complications, particularly kidney disease. However, the sensitivity of these markers compared with albumin requires further investigation.

Semicarbazide-sensitive amine oxidase activity and total nitrite and nitrate concentrations in serum: novel biochemical markers for type 2 diabetes?

The aim of this study was to evaluate the activity of semicarbazide-sensitive amine oxidase (SSAO) and the total nitrite and nitrate (NO( x )) concentrations in serum from type 2 diabetic patients and control subjects in order to evaluate if they could be used as novel diabetic markers. We studied 38 type 2 diabetic patients and 35 control subjects. Serum samples from those subjects were evaluated by radiochemical methods for SSAO activity using (14)C-benzylamine. Serum NO( x ) concentrations were obtained as an index of nitric oxide production by the Griess reaction. Serum SSAO activity was higher in type 2 diabetic patients than in control group and serum SSAO in type 2 diabetic correlated with age, serum creatinine and total cholesterol. Serum NO( x ) levels in type 2 diabetic patients were also significantly higher than those in the control group. Serum NO( x ) levels in control group correlated with serum SSAO activity. In conclusion, the increase in the SSAO activity and NO( x ) levels observed in type 2 diabetic patients could be parameters to take in account and play relevant role in diabetes development. SSAO and NO( x ) are suggested as markers for prognostic of diabetes.

Association of serum NO( x ) level with clustering of metabolic syndrome components in middle-aged and elderly general populations in Japan

OBJECTIVES

The aim of this study was to determine whether the serum nitrite plus nitrate (NO( x )) level correlates with biomarkers that are known components of the metabolic syndrome (MetS).

METHODS

Serum NO( x ) levels were measured using a commercial kit in 608 Japanese men and women between the ages of 39 and 85 years. Multivariate adjustments for age, smoking status, alcohol consumption and exercise were made in the analysis of covariance (ANCOVA). The components of the metabolic syndrome were defined based on the following criteria: body mass index (BMI) >/=25.0 kg/m(2), glycated hemoglobin (HbA1c) >/=5.6%, systolic blood pressure >/=130 mmHg or diastolic blood pressure >/=85 mmHg, high-density lipoprotein-cholesterol (HDL-C) </=1.03 mmol/l for men and </=1.29 mmol/l for women and triglyceride >/=1.69 mmol/l.

RESULTS

The logarithmically transformed age-adjusted serum NO( x ) (lnNO( x )) value was significantly higher in the low HDL-C group (1.76 +/- 0.05 mumol/l; p < 0.05) than MetS component groups (1.65 +/- 0.01 mumol/l) in men, but no difference was found in women. The means of serum lnNO( x ) after multivariate adjustment were 1.64, 1.65, 1.64, 1.66, and 1.81 mumol/l for 0, 1, 2, 3, and 4-5 MetS components for all subjects, respectively. The results of ANCOVA confirmed that the serum lnNO( x ) level was significantly correlated with the clustering of MetS components in both men and women (p < 0.0001 for trend).

CONCLUSION

Our results suggest that an increase in the clustering of MetS components was associated with the increase in serum NO levels in our general population.