Urinary peptidome and diabetic retinopathy in the DIRECT-Protect 1 and 2 trials

BACKGROUND

Given the association of diabetic retinopathy (DR) and kidney disease, we investigated the urinary peptidome to presence and deterioration of DR in a post hoc analysis of trials investigating the effect of candesartan on progression of DR in type 1 and type 2 diabetes, respectively.

METHODS

Baseline urinary peptidomic analysis was performed on a random selection of 783 and 792 subjects in two randomized controlled trials, DIRECT-Protect 1 and 2, respectively. End points were two-step (RET2) and three-step (RET3) change in Early Treatment of Diabetic Retinopathy Study protocol (ETDRS) defined level. Peptide levels were correlated to baseline EDTRS level in a discovery set of 2/3 of the participants from DIRECT-Protect 1. The identified peptides were then validated cross-sectionally in the remaining 1/3 from DIRECT-Protect 1. Thereafter, peptides identified in the discovery set were assessed in the entire DIRECT-Protect 1 and 2 cohorts and significant peptides were tested longitudinally.

RESULTS

Follow-up ranged 4.0-4.7 years. 24 peptides were associated with baseline DR in the discovery set. COL3A1 (seq: NTG~) and COL4A1 (seq: DGA~) were associated with baseline DR in the validation set (Rho: -.223, p < 0.001 and Rho: -.141, p = 0.024). Neither was significantly associated with end points. Assessing the 24 identified peptides in the entire cohorts, several collagen peptides were associated with baseline DR and end points; however, there was no overlap across diabetes types.

CONCLUSIONS

We identified several urinary peptides (mainly collagen) associated with the presence of DR, however they could not be conclusively associated with worsening of DR.

Relationship between serum bilirubin levels, urinary biopyrrin levels, and retinopathy in patients with diabetes

Objective

Previous reports have indicated that serum bilirubin levels may be associated with diabetic retinopathy. However, the detailed mechanism is not fully understood. In this study, we evaluated the relationship between the severity of diabetic retinopathy and various factors including bilirubin levels and factors influencing bilirubin metabolism.

Methods

The study participants consisted of 94 consecutive patients with diabetes mellitus admitted to Kyushu University Hospital from April 2011 to July 2012. The patients were classified into three groups: no retinopathy (NDR), simple retinopathy (SDR), and pre-proliferative or proliferative retinopathy (PDR). The relationship between the severity of retinopathy and various factors was evaluated using univariate and logistic regression analyses. In addition, multivariate regression analysis was performed to evaluate the significant determinants for bilirubin levels.

Results

In univariate analysis, a significant difference was found among NDR, SDR and PDR in bilirubin levels, duration of diabetes, systolic blood pressure, and macroalbuminuria. Logistic regression analysis showed that PDR was significantly associated with bilirubin levels, duration of diabetes, and systolic blood pressure (OR 0.737, 95% CI 0.570–0.952, P = 0.012; OR 1.085, 95% CI 1.024–1.149, P = 0.006; OR 1.036, 95% CI 1.011–1.062, P = 0.005, respectively). In turn, multivariate regression analysis showed that bilirubin levels were negatively associated with high-sensitivity C-reactive protein levels and PDR, but positively correlated with urinary biopyrrin levels, oxidized metabolites of bilirubin.

Conclusion

PDR was negatively associated with bilirubin levels. This negative association may be due to a decreased production of bilirubin rather than its increased consumption considering the positive association between bilirubin and biopyrrin levels.

Urinary neutrophil gelatinase-associated lipocalin in type 2 diabetes: Relation to nephropathy and retinopathy

BACKGROUND

Diabetes mellitus is the leading cause of end stage renal disease worldwide. Early identification of diabetic nephropathy even before appearance of microalbuminuria is a challenge for early prevention of occurrence and progression of this complication. Neutrophil gelatinase-associated lipocalin is a small protein that belongs to the lipocalin protein. Urinary neutrophil gelatinase-associated lipocalin is a promising early marker in different renal problems.

AIM OF THE WORK

To measure urinary neutrophil gelatinase-associated lipocalin in type 2 diabetic patients and to assess its role as an early marker for diagnosis of diabetic nephropathy and diabetic retinopathy.

PATIENT AND METHODS

The current study included 60 subjects with type 2 diabetes and 20 healthy control subjects. Diabetic subjects were divided into 3 groups according to urinary albumin creatinine ratio; 20 normoalbuminuric patients, 20 micro-albuminuric patients and 20 macroalbuminuric patients. They were subjected to history taking, full clinical examination, fundus examination, anthropometric measurement, urinary neutrophil gelatinase-associated lipocalin and urinary albumin creatinine ratio.

RESULTS

Urinary neutrophil gelatinase-associated lipocalin was higher in all diabetic groups than in the control group, with no difference in between diabetic groups. The difference was of great value when comparing normoalbuminuric group with control as albumin creatinine ratio was not different while the urinary neutrophil gelatinase-associated lipocalin was statistically significant (5.94 ± 1.85 ng/dl vs 1.96 ± 0.65, p < 0.001). No correlation was found with retinopathy.

CONCLUSION

Urinary neutrophil gelatinase-associated lipocalin is a sensitive marker for early detection of diabetic nephropathy even in normoalbuminuric patients denoting early tubular damage before microalbuminuria. It is not correlated with retinopathy.

Glomerular Filtration Rate and/or Ratio of Urine Albumin to Creatinine as Markers for Diabetic Retinopathy: A Ten-Year Follow-Up Study

AIMS

To determine the relationship between diabetic nephropathy and diabetic retinopathy on a population of type 2 diabetes mellitus patients.

METHODS

A prospective ten-year follow-up population-based study. We determined differences between estimated glomerular filtration rate (eGFR) using the chronic kidney disease epidemiology collaboration equation and urine albumin to creatinine ratio.

RESULTS

Annual incidence of any-DR was 8.21 ± 0.60% (7.06%-8.92%), sight-threatening diabetic retinopathy (STDR) was 2.65 ± 0.14% (2.48%-2.88%), and diabetic macular edema (DME) was 2.21 ± 0.18% (2%-2.49%). Renal study results were as follows: UACR > 30 mg/g had an annual incidence of 7.02 ± 0.05% (6.97%-7.09%), eGFR < 60 ml/min/1.73 m2 incidence was 5.89 ± 0.12% (5.70%-6.13%). Cox's proportional regression analysis of DR incidence shows that renal function studied by eGFR < 60 ml/min/1.73 m2 was less significant (p = 0.04, HR 1.223, 1.098-1.201) than UACR ≥ 300 mg/g (p < 0.001, HR 1.485, 1.103-1.548). The study of STDR shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.890, 1.267-2.820), UACR ≥ 300 mg/g (p < 0.001, HR 2.448, 1.595-3.757), and DME shows that eGFR < 60 ml/min/1.73 m2 was significant (p = 0.02, HR 1.920, 1.287-2.864) and UACR ≥ 300 mg/g (p < 0.001, HR 2.432, 1.584-3.732).

CONCLUSIONS

The UACR has a better association with diabetic retinopathy than the eGFR, although both are important risk factors for diabetic retinopathy.

Synergistic interaction between prolonged increased glycemic exposure and mildly increased urinary albumin excretion on diabetic retinopathy

The association of mild increase in urinary albumin excretion with diabetic retinopathy (DR) in clinical studies is controversial. The aim of this study is to clarify the interaction between increased glycemic exposure and mild increase in urinary albumin excretion on risk of DR.Data were collected from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2012. Overall, data from 953 participants without microalbuminuria (477 men and 476 women) were assessed. Logistic regression analysis was constructed to evaluate the association between DR and related clinical parameters, including urinary albumin-creatinine ratio (UACR, mg/g creatinine). The biological interaction of glycemic status and UACR on DR was evaluated by 3 indices: RERI, the relative excess risk due to the interaction; AP, the attributable proportion due to the interaction; and S, the additive interaction index of synergy.We found that UACR, glycated hemoglobin (HbA1c), and diabetic duration were deeply associated with increased risk of DR (UACR, odds ratio [OR] = 1.04, 95% confidence interval [CI] = 1.02-1.07; HbA1c, OR = 1.16, 95% CI = 1.04-1.30; diabetic duration, OR = 1.06, 95% CI = 1.04-1.07). Furthermore, our interaction analysis demonstrated that synergistic interaction between HbA1c and UACR on development of DR was prominent in participants with diabetic duration of ≥10 years (adjusted RERI = 0.92, 95% CI = 0.10-1.74; adjusted AP = 0.29, 95% CI = -0.82-1.41; adjusted S = 1.76, 95% CI = 1.27-2.25), but not subjects with shorter diabetic duration.These findings imply that there is the interaction between prolonged hyperglycemic exposure and increased urinary albumin excretion may exert additive synergistic effect on vascular endothelial dysfunction in the eye, even before the appearance of overt diabetic nephropathy.

Chronic Kidney Disease and Diabetic Retinopathy in Patients with Type 2 Diabetes

Purpose

To explore the relationship between chronic kidney disease (CKD) and diabetic retinopathy (DR) in a representative population of type 2 diabetes mellitus (DM2) patients in Catalonia (Spain).

Methods

This was a population-based, cross-sectional study. A total of 28,344 patients diagnosed with DM2 who had recorded ophthalmologic and renal functional examinations were evaluated. Data were obtained from a primary healthcare electronic database of medical records. CKD was defined as an estimated glomerular filtration ratio (eGFR) of <60 ml/min/1.73m² and/or urine albumin to creatinine ratio (UACR) ≥30 mg/g. DR was categorized as non-vision threatening diabetic retinopathy and vision threatening diabetic retinopathy.

Results

CKD was associated with a higher rate of DR [OR], 95% confidence interval [CI], 1.5 (1.4–1.7). When we analyzed the association between different levels of UACR and DR prevalence observed that DR prevalence rose with the increase of UACR levels, and this association was significant from UACR values ≥10 mg/g, and increased considerably with UACR values ≥300mg/g (Odds ratio [OR], 95% confidence interval [CI], 2.0 (1.6–2.5). This association was lower in patients with eGFR levels 44 to 30 mL/min/1.73m² [OR], 95% confidence interval [CI], 1.3 (1.1–1.6).

Conclusions

These results show that CKD, high UACR and/or low eGFR, appear to be associated with DR in this DM2 population.

Decreased urine uric acid excretion is associated with diabetic retinopathy but not with lower limb atherosclerosis in hospitalized patients with type 2 diabetes

OBJECTIVE

To explore the associations between urine uric acid excretion (UUAE) and diabetic retinopathy (DR)/lower limb atherosclerotic lesions in hospitalized Chinese patients with type 2 diabetes.

METHODS

This cross-sectional study was conducted in 2529 hospitalized Chinese patients with type 2 diabetes. UUAE was determined enzymatically using a single 24-h urine collection. The subjects were stratified into quartile based on UUAE levels. DR was determined by digital fundus photography. Lower limb atherosclerotic lesions were assessed by Doppler ultrasound. Both DR and lower limb atherosclerosis were compared among the UUAE quartile groups, respectively.

RESULTS

There was a significant decrease in the prevalence of DR in patients across the UUAE quartiles after adjustment for sex, age and diabetic duration (35.0%, 30.7%, 26.1%, and 21.5%, respectively, p = 0.000001 for trend). A fully adjusted multiple logistic regression analyses revealed that UUAE quartiles were markedly inversely associated with the presence of DR (p = 0.030). The prevalence of lower limb plaque (73.9% vs. 62.6%, p = 0.000044) and stenosis (16.3% vs. 9.7%, p = 0.000015) was markedly higher in the diabetics with DR than in those without DR. However, there was no statistical association between the UUAE and lower limb atherosclerotic lesions in type 2 diabetes.

CONCLUSIONS

Decreased UUAE was an independent risk factor for DR but not for lower limb atherosclerosis in hospitalized Chinese patients with type 2 diabetes. In selected populations, such as those with type 2 diabetes, the role of uric acid in atherosclerosis may be result from other concomitantly atherosclerotic risk factors, such as DR.

Changes in urine proteome accompanying diabetic nephropathy progression

INTRODUCTION

Owing to the prevalence of type 2 diabetes, diabetic kidney disease (DKD) becomes the major cause of end-stage renal disease. The current markers of diabetic nephropathy are based on albuminuria and clinical signs of retinopathy. Sensitive and specific noninvasive diagnostic tools, unbiased by the presence of comorbidities, are needed, especially to detect the early stages of diabetic complications.

OBJECTIVES

The aim of the study was to analyze changes in urinary protein excretion based on the stage of DKD using quantitative proteomics.

PATIENTS AND METHODS

A total of 27 healthy controls were age- and sex-matched to 72 diabetes patients classified into 3 groups: no signs of retinopathy or nephropathy (n = 33), retinopathy but no microalbuminuria (n = 15), and diabetic nephropathy (DN) based on overt albuminuria or microalbuminuria with retinopathy (n = 24). To assess the intergroup differences, samples were partially pooled, tagged using 8-plex iTRAQ reagents, and the resulting peptide mixture was resolved by isoelectrofocusing. The obtained fractions were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data were analyzed using the MASCOT software and dedicated in-house proteomic data analysis programs.

RESULTS

The changes in the urine proteome following DKD progression involved some known protein markers of DN and several other proteins. Decreased levels of some proteins are presumably related to impaired secretory function of other organs affected by diabetes. In particular, a diminished excretion of pancreatic amylase and deoxyribonuclease I suggested exocrine pancreatic insufficiency (EPI), coexisting with type 2 diabetes.

CONCLUSIONS

A decrease in the urinary excretion of some pancreatic enzymes suggests EPI associated with diabetes. This hypothesis is yet to be verified; nevertheless, renal and extrarenal confounders must be considered when interpreting the results of quantitative urinary proteomics.  

Higher dietary salt intake is associated with microalbuminuria, but not with retinopathy in individuals with type 1 diabetes: the EURODIAB Prospective Complications Study

AIMS/HYPOTHESIS

High dietary salt intake has been associated with elevated BP and may also have a deleterious effect on microvascular complications. We studied the cross-sectional associations between dietary salt intake (estimated from 24 h urinary sodium excretion) and urinary potassium excretion on the one hand, and the prevalence of microvascular complications on the other, in individuals with type 1 diabetes.

METHODS

We measured sodium and potassium concentrations in two 24 h urine samples in 1,212 individuals with type 1 diabetes (40 ± 10 years old, 51% men) who participated in the EURODIAB Prospective Complications Study. We used multiple logistic regression analyses to investigate associations between dietary salt intake and microvascular complications adjusted for age and sex, and additionally for BMI, smoking, urinary potassium excretion, antihypertensive medication and physical activity, and total energy, protein, alcohol, saturated fat and fibre intake.

RESULTS

After full adjustment, 1 g/day higher dietary salt intake was positively associated with the presence of microalbuminuria (OR 1.06 [95% CI 1.01, 1.10]), but not macroalbuminuria (OR 0.99 [95% CI 0.94, 1.05]), non-proliferative retinopathy (OR 1.00 (95% CI 0.96, 1.04]) or proliferative retinopathy (OR 1.02 (95% CI 0.95, 1.08]). After excluding individuals with cardiovascular disease and/or antihypertensive medication (n = 418), we found a non-significant association with microalbuminuria (OR 1.04 [95% CI 0.99, 1.10]) and macroalbuminuria (OR 1.05 [95% CI 0.96, 1.16]). The association between dietary salt intake and microalbuminuria was stronger in individuals with a BMI above 25 kg/m(2) (OR 1.11 [95% CI 1.04, 1.18]) than in those with BMI below 25 kg/m(2) (OR 1.03 [95% CI 0.97, 1.09]). No significant associations were found between urinary potassium excretion and microvascular complications.

CONCLUSIONS/INTERPRETATION

In individuals with type 1 diabetes, higher dietary salt intake, as determined by 24 h urinary sodium excretion, may be positively associated with microalbuminuria, particularly in overweight individuals.

Urinary 6-sulfatoxymelatonin level in diabetic retinopathy patients with type 2 diabetes

Melatonin is a powerful antioxidant. Decreased melatonin excretion has been reported to be associated with several oxidative stress-related diseases. The urinary metabolite of melatonin, 6-sulfatoxymelatonin (aMT6s), has proved to be a very reliable index of melatonin production. The present study aims to evaluate the level of urinary aMT6s in patients with type 2 diabetes mellitus and diabetic retinopathy. Urine samples were collected from 10 patients with diabetes and no diabetic retinopathy (NDR), 19 patients with nonproliferative diabetic retinopathy (NPDR), 38 patients with proliferative diabetic retinopathy (PDR), and 16 subjects without diabetes mellitus, who served as controls. The level of aMT6s in specimens was assayed by a commercial aMT6s ELISA kit, creatinine levels were also measured for each sample to get urinary aMT6s/creatinine ratio. Creatinine-adjusted urinary aMT6s values were compared among four groups. The urinary aMT6s (mean ± SD) levels were 9.95 ± 2.42, 9.90 ± 2.28, 8.40 ± 1.84 and 5.58 ± 1.33 ng/mg creatinine in the controls and in patients with NDR, NPDR, or PDR, respectively. The urinary aMT6s level of the PDR group was significantly lower than that of the control, NDR and DR groups. No significant difference was found among the control, NDR and DR groups. After adjustment for various factors (age, smoking, cancer, and coronary heart disease) that may influence the aMT6s level, the odds-ratio of urinary aMT6s comparing PDR patients to controls was 0.246 (95% confidence interval = 0.108-0.558, P = 0.001). Therefore, the urinary aMT6s level is significantly decreased in diabetic patients with PDR but not in diabetic patients without PDR, which indicates that decreased urinary aMT6s level may be associated with the pathogenesis of PDR.

Atherogenic lipids and vascular complications in a selected diabetic population with normal urinary albumin/creatinine ratios

OBJECTIVE

To test the hypothesis that at different urinary albumin/creatinine ratios within the normal ranges, diabetics have low but similar prevalence of metabolic and micro vascular disease.

METHODS

The study sample consisted of normotensive diabetics not taking any medications known to effect blood pressure and lipids. The data were collected from the Diabetes Register. The diabetics were subgrouped according to the urinary albumin/creatinine ratios. MA is defined as present if the albumin/creatinine ratio (ACR) is more than 2 mg/mmol.

RESULTS

MA was present in 16% of the 152 diabetics. Total cholesterol, systolic BP, and triglycerides were significantly high in diabetics with ACR≥1<2 compared with <1. The prevalence rates for retinopathy and neuropathy in the MA group were also significantly high. However, a large number of diabetics without MA had had established complications (37% retinopathy, 40% neuropathy, and 16% peripheral vascular disease). Because these results were based on single early morning urine samples, we looked at their MA in the past year. After exclusion of regressed and progressed groups, the complications rate remained the same.

CONCLUSION

The high prevalence of metabolic and vascular complications seen even in absence of MA indicates an early intervention and those diabetics should not wait unitl CVD risk scores raise to receive preventive treatment.

[Change and significance of urinary smad3 in type 2 diabetic nephropathy]

OBJECTIVE

To explore the significance of urinary smad3(usmad3) protein level change in diabetic nephropathy (DN) in type 2 diabetes mellitus and examine its relationship with the progression of DN.

METHODS

From May 2010 to August 2011, a total of 282 patients with type 2 diabetes were selected for the experimental group according to instant urine specimen albumin-creatinine ratio (UACR). Another 100 healthy subjects were taken as the control group. Then the diabetics were divided into 3 groups, including 110 with normal albuminuria (NA group), 114 with microalbuminuria (MA group) and 58 with macroalbuminuria (DN group). Enzyme-linked immunosorbent assay (ELISA) was used to detect the content of usmad3. The parameters of age, systolic blood pressure, body mass index (BMI), blood glucose, blood lipids, urinary albumin/creatinine (ACR), estimated glomerular filtration rate (eGFR) and glycosylated hemoglobin were measured. And non-mydriatic fundus camera was used to evaluate retinopathy, the DN group (n = 58) was then divided into two groups of those without retinopathy (n = 25) and with retinopathy (n = 33).

RESULTS

(1) The usmad3 level in type 2 diabetes group was significantly higher than that in the control group (489(273,1193) vs 311 (179, 497) ng/mmol Cr (P < 0.01). (2) According to UACR, type 2 diabetes group was divided into 3 different groups to compare the relative level differences of usmad3 in different groups: MA group versus NA group, 552 (316,1338) vs 317 (200,594), DN group versus NA group, 1035 (503,3035)vs 317 (200,594), DN group versus MA group, 1035(503,3035)vs 552(316,1338), all P < 0.01. (3) Pearson correlation test showed the level of usmad3 was significantly correlated with age, SBP, HbA1c, blood urea nitrogen, creatinine, total cholesterol, low density lipoprotein, eGFR and UACR (r = 0.57, P < 0.01). And multiple linear regression analysis showed that usmad3 and UACR were independently correlated (β = 0.754, P < 0.01). (4) The usmad3 level in DN with retinopathy were significantly higher than that in DN without retinopathy (1905(806,4303) vs 595 (331,1183), P < 0.01). No significant difference existed in uACR level between DN with retinopathy and DN without retinopathy(P > 0.05).

CONCLUSIONS

Urinary level of smad3 is significantly elevated in type 2 diabetics and it is significantly associated with ACR. It suggests that usmad3 is a potential marker in the diagnosis of DN and may be used to predict the severity of DN.

Association of serum YKL-40 levels with urinary albumin excretion rate in young Japanese patients with type 1 diabetes mellitus

YKL-40 is a marker of inflammation and endothelial dysfunction, both of which play important roles in the progression of diabetic complications. However, little information has been obtained about serum YKL-40 levels in type 1 diabetic patients. We evaluated YKL-40 levels and its association with diabetic micro- and macroandgiopathy in 131 young Japanese type 1 diabetic patients without advanced diabetic complications (aged 24.7±5.9 years) and 97 age- and gender-matched healthy controls. YKL-40 levels were significantly elevated in type 1 diabetic patients than in healthy controls (median (range) 46.4 (20.3-136.7) and 52.3 (21.4-274.1) ng/mL, respectively, p = 0.003). There was a significant positive association between YKL-40 levels and urinary albumin creatinine ratio (UACR) (r = 0.226, p = 0.013). Furthermore, a multivariate regression analysis demonstrated that YKL-40 levels were a determinant of UACR independently of conventional risk factors. In addition, YKL-40 levels were significantly higher in participants with diabetic retinopathy compared to those without it (median (range) 55.5 (23.3-274.1) and 50.3 (21.4-237.4) ng/mL, respectively, p = 0.039). Serum YKL-40 levels were elevated in type 1 diabetic patients and associated with increasing level of albuminuria. YKL-40 could be a predictor to assess the risk of diabetic microangiopathy in the early stage in type 1 diabetic patients.

Protease profiling of different biofluids in type 1 diabetes mellitus

OBJECTIVES

We aimed to disclose the proteolytic events underlying type 1 diabetes and related complication through protease profiling in the bodily fluids serum, urine and saliva.

DESIGN AND METHODS

Zymography followed by LC-MS/MS was performed for protease identification and quantitative comparison of proteolytic activity between healthy, type 1 diabetic patients with no complications and with retinopathy and nephropathy. Western blotting was also accomplished for MMP-9 and MMP-2 identification and expression analysis.

RESULTS

Only MMP-2 and MMP-9 were observed in serum with significantly increased levels and activity observed in diabetic patients. In urine and saliva other proteases besides MMPs were identified by MS and presented disease-dependent activity variations. Among these are complex MMP-9/Neutrophil gelatinase-associated lipocalin, aminopeptidase N, azurocidin and kallikrein 1 with more activity noticed in type 1 diabetes patients with nephropathy and/or retinopathy.

CONCLUSION

Our data highlight the usefulness of urine and saliva for the monitoring of type-1 diabetes-related proteolytic events, where aminopeptidase N, azurocidin and kallikrein 1 appear as promising screening targets for type 1 diabetes-related complications.

A microalbuminuria threshold to predict the risk for the development of diabetic retinopathy in type 2 diabetes mellitus patients

Objective

To test the hypothesis that a microalbuminuria (MA) threshold can help predict the risk for the development of diabetic retinopathy (DR) in type 2 diabetes mellitus (T2DM)_ patients.

Design

We conducted a cross-sectional study of 4739 subjects with T2DM and a prospective study of 297 subjects with T2DM in China respectively.

Methods

Clinical and laboratory data were collected and biologic risk factors associated with any DR were analysed.

Results

In the cross-sectional study, we found that MA was an independent risk factor for DR development; further, when the patients were divided into MA deciles, odds ratio (ORs) of DR for the patients in the sixth MA decile (10.7 mg/24 h) was 1.579-fold (1.161–2.147) compared to that for patients in the first MA decile. Furthermore, the OR of DR increased with a gradual increase in MA levels. Similarly, in the prospective study, during a mean follow-up of 4.5 years, we found that 51 patients (29.0%) of the 176 subjects with high MA level (10.7–30 mg/24 h) developed DR, while 17 patients (14.1%) of the 121 subjects with lower MA (<10.7 mg/24 h) developed DR, and the relative risk ratio of the development of DR is 2.13(95% CI, 1.58–3.62, P<0.001).

Conclusion

These data suggest that an MA threshold can predict the risk for the development of DR in type 2 diabetes mellitus, although it is still within the traditionally established normal range.

Compliance with screening guidelines for diabetic retinopathy in a large academic children's hospital in the Bronx

OBJECTIVE

As the rate of type 2 diabetes mellitus (DM) in children is increasing, the number of children with complications of DM, such as retinopathy, will also increase. American Diabetes Association and American Academy of Pediatrics guidelines recommend annual eye exams for children with type 1 DM who are older than 10 years, starting 3-5 years after diagnosis. Adolescents with type 2 DM should have an exam when diagnosed. This study was designed to determine if these guidelines are followed and to determine factors that influence providers to follow them.

PATIENTS AND METHODS

We identified all 15- to 20-year-old patients seen in a pediatric diabetes clinic over 6 months. All patients with type 2 DM and those with type 1 DM diagnosed at least 5 years prior were included. Charts were reviewed for 18 months to determine whether patients were referred for an eye exam. Data extracted included demographics, DM type, DM duration, hemoglobin A(1C), and presence of microalbuminuria.

RESULTS

Of 80 patients, 28 (35%) were referred for an eye exam. Patients with a longer duration of DM (P=.006) and those with microalbuminuria (P=.02) were more likely to be referred for screening.

CONCLUSIONS

As only 35% of the patients in this study were referred for eye exams, patients at risk for retinopathy are missing opportunities for screening and early treatment. With the increasing number of children with type 2 DM, more patients will be at risk for retinopathy and its consequences. Pediatricians and endocrinologists should be educated about referring for annual eye exams.

Urinary pigment epithelium-derived factor as a marker of diabetic nephropathy

BACKGROUND

Pigment epithelium-derived factor (PEDF), a serine protease inhibitor, regulates extracellular matrix production in the kidney. We sought the association between urinary PEDF (uPEDF) and development of nephropathy among patients with type 2 diabetes (T2DM).

METHODS

Two human studies were performed in which uPEDF was determined by ELISA. These studies included (1) a cross-sectional study of T2DM (n = 228) and healthy controls (n = 46) [corrected] and (2) a longitudinal study of hypertensive T2DM with microalbuminuria (MA; n = 42) treated with irbesartan for 6 months. An animal study was performed in which PEDF was measured in the kidney and urine samples of control rats, rats rendered diabetic with streptozotocin that were also fed a high-fat diet, and diabetic rats treated with irbesartan for 3 months.

RESULTS

Cross-sectional study: compared to controls, uPEDF was significantly higher in patients with diabetic nephropathy. uPEDF independently correlated with MA. In the MA group, uPEDF in patients with diabetic retinopathy was significantly higher than that in patients without diabetic retinopathy. Longitudinal study: irbesartan significantly decreased uPEDF in T2DM with MA. Animal study: in diabetic rats, increased PEDF was observed in both the urine and kidney samples. uPEDF showed a significant correlation with the expression of PEDF in the kidney. Irbesartan could significantly decrease the PEDF expression in the kidneys of diabetic rats as well as uPEDF.

CONCLUSION

uPEDF may serve as a novel marker for screening for nephropathy among patients with T2DM and monitoring the response to therapy.

Normoalbuminuric type 1 diabetic patients with retinopathy have an impaired tubular response to desmopressin: its relationship with plasma endothelin-1

OBJECTIVE

The aim of the study was to evaluate whether normoalbuminuric type 1 diabetic patients with diabetic retinopathy (DR) have an impaired tubular response to desmopressin (dDAVP, a synthetic analog of vasopressin) administration, and its relationship with plasma and urine endothelin-1 (ET-1) levels.

DESIGN

This was an interventional case-control study.

SETTING

The study was conducted at a referral center.

PARTICIPANTS

Fifteen normoalbuminuric type 1 diabetic patients with DR were compared with 30 normoalbuminuric type 1 diabetic patients without DR. Both groups were matched by age, gender, body mass index, glycosylated hemoglobin, and the main laboratory markers of kidney function.

INTERVENTION

After a 12-h period of water deprivation, dDAVP (0.3 microg/kg) was infused over 20 min. Urine was collected at baseline and 1, 2, and 3 h after dDAVP administration. ET-1 was assessed by ELISA.

RESULTS

dDAVP induced a lower rise in urine osmolality in patients with DR (from 650 +/- 206 to 754 +/- 224 mosmol/kg; P = 0.02) than in diabetic patients without DR (from 714 +/- 194 to 905 +/- 163 mosmol/kg; P < 0.0001). In addition, fractional excretion of Na+ decreased in patients without DR (from 0.45 +/- 0.30 to 0.29 +/- 0.29%; P = 0.04) but not in the diabetic patients with DR (from 0.36 +/- 0.22 to 0.36 +/- 0.40%; P = 0.96). Plasma ET-1 levels were inversely correlated with the response of urinary osmolality after dDAVP administration (r = -0.62; P = 0.008).

CONCLUSIONS

Normoalbuminuric type 1 diabetic patients with DR have impaired renal response to dDAVP that is related to plasma ET-1 levels. Further studies are required to elucidate whether this tubular resistance to dDAVP might favor dehydration in these patients.

Plasma apelin and asymmetric dimethylarginine levels in type 2 diabetic patients with diabetic retinopathy

Oxidative stress is thought to be one of the underlying mechanisms of diabetic microvascular complications such as diabetic nephropathy and diabetic retinopathy (DRP). Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthase inhibitor and increased by oxidative stress. Apelin is an endogenous ligand for human orphan G-protein-coupled receptor, APJ and increases NO generation. In this study, our aim was to evaluate ADMA and apelin levels in diabetic patients with or without retinopathy and their relationships between retinopathy stages and metabolic parameters. Seventy-nine diabetic patients were included into the study and classified into three groups. Group 1 consisted of 41 patients with no DRP (NDRP), group 2 consisted of 23 patients with nonproliferative DRP (NPDRP), and group 3 consisted of 15 patients with proliferative DRP (PDRP). Plasma ADMA and apelin levels were found to be similar in all groups. But, there was a positive correlation between apelin levels and urinary albumin/creatinine ratio. Further studies involving larger patients populations and healthy controls should be done to clarify the pathogenetic significance of ADMA and apelin in diabetic microvascular complications.

Cardiovascular autonomic dysfunction predicts acute ischaemic stroke in patients with Type 2 diabetes mellitus: a 7-year follow-up study

AIMS

We investigated whether cardiovascular autonomic neuropathy (CAN) is associated with acute ischaemic stroke in patients with Type 2 diabetes.

METHODS

From 1999 to 2000, cardiovascular autonomic function tests were conducted in patients with Type 2 diabetes (n = 1458). Patients were followed up between 2006 and 2007. Standard tests for CAN measured heart rate variability parameters [expiration-to-inspiration (E/I) ratio, responses to the Valsalva manoeuvre and standing]. Using the American Diabetes Association criteria, the CAN scores were determined from the results of each test as follows: 0 = normal, 1 = abnormal (total maximum score 3). We assessed the development of acute ischaemic stroke events.

RESULTS

The prevalence of CAN at baseline was 55.7% (E/I 17.1%, Valsalva 39.4%, posture 27.3%) (n = 1126). During follow-up, 131 patients (11.6%) developed acute ischaemic stroke. The vascular events were more frequent in older patients (P < 0.001) and in those with diabetes of longer duration (P = 0.022), hypertension (P < 0.001) or diabetic retinopathy (P = 0.03) than in patients without vascular events. Patients with ischaemic stroke had higher creatinine levels (P = 0.045) and higher urine albumin excretion (P = 0.025) than those of patients without stroke. Cox proportional hazard regression analysis revealed that the CAN score was associated with the development of acute ischaemic stroke (total score 0 vs. 3, adjusted hazard ratio 2.7, 95% CI 1.3-5.5, P = 0.006).

CONCLUSION

Cardiovascular autonomic dysfunction was significantly associated with the development of ischaemic stroke in patients with Type 2 diabetes.

Role of blood pressure in development of early retinopathy in adolescents with type 1 diabetes: prospective cohort study

OBJECTIVE

To examine the relation between blood pressure and the development of early retinopathy in adolescents with childhood onset type 1 diabetes.

DESIGN

Prospective cohort study.

SETTING

Diabetes Complications Assessment Service at the Children's Hospital at Westmead, Sydney, Australia.

PARTICIPANTS

1869 patients with type 1 diabetes (54% female) screened for retinopathy with baseline median age 13.4 (interquartile range 12.0-15.2) years, duration 4.9 (3.1-7.0) years, and albumin excretion rate of 4.4 (3.1-6.8) microg/min plus a subgroup of 1093 patients retinopathy-free at baseline and followed for a median 4.1 (2.4-6.6) years.

MAIN OUTCOME MEASURES

Early background retinopathy; blood pressure.

RESULTS

Overall, retinopathy developed in 673 (36%) participants at any time point. In the retinopathy-free group, higher systolic blood pressure (odds ratio 1.01, 95% confidence interval 1.003 to 1.02) and diastolic blood pressure (1.01, 1.002 to 1.03) were predictors of retinopathy, after adjustment for albumin excretion rate (1.27, 1.13 to 1.42), haemoglobin A(1c) (1.08, 1.02 to 1.15), duration of diabetes (1.16, 1.13 to 1.19), age (1.13, 1.08 to 1.17), and height (0.98, 0.97 to 0.99). In a subgroup of 1025 patients with albumin excretion rate below 7.5 microg/min, the cumulative risk of retinopathy at 10 years' duration of diabetes was higher for those with systolic blood pressure on or above the 90th centile compared with those below the 90th centile (58% v 35%, P=0.03). The risk was also higher for patients with diastolic blood pressure on or above the 90th centile compared with those below the 90th centile (57% v 35%, P=0.005).

CONCLUSIONS

Both systolic and diastolic blood pressure are predictors of retinopathy and increase the probability of early retinopathy independently of incipient nephropathy in young patients with type 1 diabetes.

Endothelin-1 levels and albuminuria in patients with type 2 diabetes mellitus

AIM

To evaluate the relationship of plasma endothelin-1 (ET-1) levels, a marker of endothelial dysfunction, and urinary albumin excretion in patients with type 2 diabetes mellitus (DM).

METHODS

Cross-sectional study was conducted in 279 patients (132 males, mean age: 58.7+/-11.0 years, mean DM duration: 11.3+/-8.1 years). Urinary albumin excretion, ET-1, and insulin were measured. Insulin sensitivity was estimated by homeostasis model assessment (HOMA-ir) index.

RESULTS

ET-1 was associated with urinary albumin excretion after controlling for age, gender, body mass index, blood pressure, HbA1c test, and total cholesterol (R=0.436; adjusted R(2)=0.190, P<0.01). Furthermore, there was a progressive increase in plasma ET-1 levels from patients with normoalbuminuria (n=187, 0.92+/-0.50pg/ml), microalbuminuria (n=68, 1.13+/-0.52pg/ml) to macroalbuminuria (n=24, 1.93+/-1.10pg/ml, P<0.01).

CONCLUSION

There is an independent association of plasma ET-1 levels with urinary albumin excretion. In addition, plasma ET-1 levels started to increase in the normal values of urinary albumin excretion suggesting that in patients with type 2 DM endothelial dysfunction is already present, in urinary albumin excretion values considered normal.

[Urinary excretion of proinflammatory cytokines and transforming growth factor beta at early stages of diabetic nephropathy]

AIM

To examine correlations between urine excretion of proinflammatory cytokines, transforming growth factor beta (TGF-b) and changes in renal structure and function, quality of glycemia control in patients with type 1 diabetes mellitus.

MATERIAL AND METHODS

Urinary excretion of interleukine 1-beta (IL-1b), monocytic chemoattractive protein-1 (MCP-1), RANTES and TGF-b was measured with enzyme immunoassay in 57 patients including 22 patients with normal albuminuria, 23--with microalbuminuria, 12--with macroalbuminuria. Creatinine clearance was subnormal in 8 patients with macroalbuminuria. The control group consisted of 10 healthy persons. Morphological examination of renal biopsies was performed in 8 patients with normoalbuminuria and 10 patients with microalbuminuria.

RESULTS

Patients with normoalbuminuria had excretion of MCP-1 significantly higher than in controls. Microalbuminuria patients showed high excretion of IL-1b, MCP-1 and TGF-b. Excretion of IL-1b, MCP-1, RANTES and TGF-b in patients with macroalbuminuria was higher than in controls and other groups of patients. Excretion of cytokines and TGFb correlated inversely with glomerular filtration rate and hemoglobin level. Positive correlations were detected between excretion of IL-1b, MCP-1, TGFb and glycated hemoglobin A(1c). In patients with normo- and microalbuminuria cytokine and TGFb excretion correlated with thickness of glomerular and glomerular basal membrane. CD68-positive macrophages were detected in the intersticium of 1 patient with normoalbuminuria and 6 patients with microalbuminuria.

CONCLUSION

Urinary excretion of proinflammatory cytokines and TGF-b was elevated in patients with DM-1 having micro- and macroalbuminuria suggesting participation of inflammation in development of diabetic nephropathy.

Plasma ghrelin concentrations in different clinical stages of diabetic complications and glycemic control in Japanese diabetics

Ghrelin is an acylated 28-amino-acid peptide that stimulates food intake, GH secretion, and gastric motility. Experimental studies have suggested that ghrelin plays roles in glucose homeostasis, atherosclerosis, and microangiopathy. We investigated possible involvement of ghrelin in micro- and macro-vascular diabetic complications and glycemic control in diabetic patients. Fasting and postprandial plasma ghrelin concentrations after a test meal were measured in 108 and 61 Japanese diabetic patients, respectively. Plasma ghrelin concentrations were negatively correlated with body mass index (BMI) (r = -0.309, P = 0.002) or HbA(1c) (r = -0.264, P = 0.0065). Plasma ghrelin levels in patients with diabetic nephropathy who showed high serum creatinine levels (s-Cre) were significantly higher than those in patients who showed normal s-Cre (P<0.02). In patients with diabetic triopathy, plasma ghrelin concentrations were significantly lower than those in patients without diabetic complications (P<0.05). Stepwise multiple regression analyses revealed that s-Cre, BMI, and HbA(1c) were independently associated with plasma ghrelin levels. A postprandial decrease of ghrelin was observed in patients with normal CV(R-R) values or those with normal body weight, whereas it was not seen in obese patients or in patients with low CV (R-R) values. Suppression rates of ghrelin 30-60 min after a test meal in obese patients were significantly lower than those in normal-weight patients. These findings suggest that ghrelin secretion is suppressed by long-term hyperglycemia and that obesity influences the regulation of ghrelin secretion.

Association between serum testosterone concentration and collagen degradation fragments in men with type 2 diabetes mellitus

The aim of the present study was to evaluate relationships between serum endogenous androgens and urinary concentration of cross-linked N-telopeptides of type I collagen (NTx), a bone resorption marker, in men with type 2 diabetes mellitus because low androgen concentrations are associated with both osteoporosis and cardiovascular disease. Relationships between serum free testosterone and urinary NTx concentrations were investigated in 246 consecutive men with type 2 diabetes mellitus. In addition, relationships between urinary NTx concentration and other variables including age, duration of diabetes, blood pressure, serum lipid concentration, hemoglobin A(1c), and body mass index were evaluated. Urinary NTx concentrations were 27.8 (26.4-29.3) nmol of bone collagen equivalent per millimole of creatinine, correlating inversely with serum free testosterone (r = -0.263, P < .0001). Multiple regression analysis identified serum free testosterone (beta = -.292, P < .0001), hemoglobin A(1c) (beta = .144, P = .0404), and smoking status (beta = .143, P = .0402) as independent determinants of urinary NTx. In conclusion, serum free testosterone concentration correlated inversely with urinary NTx concentration, which may partly account for an observed link between osteoporosis and cardiovascular disease in men with type 2 diabetes mellitus.

Microalbuminuria is a major determinant of elevated plasma retinol-binding protein 4 in type 2 diabetic patients

Plasma retinol-binding protein 4 (RBP4) may be a new adipokine linked to obesity-induced insulin resistance and type 2 diabetes. The impact of diabetic nephropathy on plasma RBP4 levels, however, is not known. We tested the hypothesis that microalbuminuria is associated with elevated plasma concentrations of RBP4 in type 2 diabetic subjects. Retinol, its binding protein and transthyretin (TTR) were measured in the plasma and urine of 62 type 2 diabetic subjects, 26 of whom had microalbuminuria. The results were compared to 35 healthy control subjects. Despite no differences in plasma retinol, concentrations of the RBP4 were significantly elevated in plasma of diabetic patients and significantly higher in those with microalbuminuria. The higher plasma levels of the binding protein in subjects with microalbuminuria were accompanied by both significantly elevated plasma TTR and increased urinary levels of RBP4. There were no correlations of plasma-binding protein levels and parameters of insulin resistance. Our study suggests that plasma RBP4 levels in type 2 diabetic patients are affected by incipient nephropathy. Therefore, further studies evaluating RBP4 as a regulator of systemic insulin resistance and type 2 diabetes will need to take renal function into consideration.

Early changes in glomerular size selectivity in young adults with type 1 diabetes and retinopathy. Results from the Diabetes Incidence Study in Sweden

OBJECTIVE

To investigate the relationship between early-onset retinopathy and urinary markers of renal dysfunction.

RESEARCH DESIGN AND METHODS

The Diabetes Incidence Study in Sweden (DISS) aims to register all new cases of diabetes in young adults (15-34 years). In 1987-1988, 806 patients were reported and later invited to participate in a follow-up study focusing on microvascular complications after approximately 10 years of diabetes. In the present study, 149 patients with type 1 diabetes, completed eye examination, and urine sampling were included.

RESULTS

The patients with retinopathy (n=58, 39%) had higher HbA(1c) (P<.001) and urinary IgG2/creatinine (P<.05) and IgG2/IgG4 ratios (P<.05). Patients with maculopathy had the highest levels. No significant differences in urinary albumin/creatinine, glycosaminoglycans (GAGs)/creatinine, Tamm-Horsfall protein (THP)/creatinine, and IgG4/creatinine ratios were found. Women had higher urinary albumin/creatinine (P<.01) and urinary IgG2/creatinine ratios (P<.01) than men.

CONCLUSIONS

Young adults with type 1 diabetes and early-onset retinopathy had higher IgG2/creatinine and IgG2/IgG4 ratios than patients without retinopathy indicating that retinopathy is associated with a change in glomerular size selectivity. This was found in association with normal urinary albumin and THP excretion and may be suspected to reflect early general vascular changes.

Erythrocyte membrane anionic content and urinary glycosaminoglycan excretion in type 1 diabetes: association with retinopathy

BACKGROUND

In diabetic nephropathy, increased excretion of glycosaminoglycans and loss of basement membrane anionic charge had been documented to be related with diabetic microalbumuniria. There was no study that studied those two factors in clinical settings with a degree of diabetic retinopathy in type 1 diabetics.

METHOD

Forty subjects (aged 27.3 +/- 6.3) with type 1 diabetes with different levels of diabetic retinopathy and 30 healthy subjects (aged 29.52 +/- 8.7) were included in the study. Subjects were first divided as patients without (R0) and with (R1) retinopathy. They then were further divided into two subgroups with the help of fundus angiography as diabetic lesions demonstrable with fluorescein angiography (R1A) and early diabetic retinopathy lesions on fundus examination (R1B). Erythrocyte anionic charge (EAC) was determined by the binding of cationic dye, alcian blue, and urinary glycosaminoglycan excretion and (UGAG) was determined spectrophotometrically.

RESULTS

UGAG was increased (35.74 +/- 14.01 vs 21.25 +/- 6.19 micro g/mL, 95% confidence intervals [CI], 9.01-19.96, p = 0.02) and EAC (62.14 +/- 27.17 vs. 158.53 +/- 36.98 ng alcian blue 106 per 106 RBC, 95% [CI] -111.68-81.10, p = 0.0001) was decreased significantly in diabetic patients with respect to controls. As the grade of diabetic retinopathy increased, UGAG increased and EAC decreased within subgroups of diabetic patients (p < 0.005). UGAG positively correlated (r = 0.36 and p = 0.03) and EAC negatively (r = -0.695, p = 0.0001) correlated with diabetes duration. EAC and UGAG negatively correlated (r = -0.58 and p = 0.0001) with each other in type 1 diabetics. EAC (p = 0.007) and diabetes duration (p = 0.001) were found to be the two significant factors to have diabetic retinopathy in diabetics with logistic regression analysis.

CONCLUSION

Although we need more prospective and larger studies to get a direct conclusion, we found that type 1 diabetic patients with less EAC and more UGAG are more likely to have diabetic retinopathy.

[Interleukin 12 as an anti-angiogenic mediator in type 1 diabetic children]

The objective of the study was to analyse levels IL-12 and to relate the findings to the clinical course of type 1 diabetes mellitus (DM1).

MATERIAL AND METHODS

We examined a group of 102 children with DM1 and 39 healthy children (as the control). All the children with DM1 had their daily urine albumin excretion, HbA1c, C-peptide measured, 24hrs blood pressure monitoring and ophthalmologic examination. In accordance to the ophthalmologic examination and level IL-12 in the serum the diabetic children were divided into 3 groups: group A: IL-12>0 pg/ml; group B: IL-12=0 pg/ml; group C: IL-12=0 pg/ml and IL12>0 pg/ml. Serum levels of IL-12 and TNFalpha were measured by the immunoenzymatic ELISA method, Quan-tikine High Sensitivity Human by R&D Systems (USA).

RESULTS

Children of group A were characterized by significantly high level of IL-12 and by the absence of TNFalpha as compared with the children of group B, who had undetectable IL-12 along with high TNFalpha level. Additionally, children of group A had significantly lower urine albumin excretion and had only developed retinopathy. However, the children of group B not only had retinopathy, nephropathy but also arterial hypertension. The patients of group A were also analysed against the children of group C, who were characterized by high IL-12 level and some of them had also detectable TNFalpha, but without retinopathy and nephropathy.

CONCLUSIONS

The results of our study imply the existence of balance between IL-12 and TNFalpha in type 1 DM children, which seems to warrant the stage of disease without diabetic complications. However, the IL-12 domination tends to prevent or delay nephropathy development but does not protect from retinopathy.

Soluble vascular cell adhesion molecule-1 and soluble E-selectin are associated with micro- and macrovascular complications in Type 1 diabetic patients

OBJECTIVE

There are no large studies in Type 1 diabetic patients that have examined the relation between soluble adhesion molecules and micro- and macrovascular outcomes, although the risks of such complications are high. Therefore, the main objective is to examine the relationship between soluble (s) vascular cell adhesion molecule-1 (sVCAM-1) and sE-selectin and retinopathy, albuminuria, and cardiovascular disease (CVD) in Type 1 diabetic patients.

METHODS

Cross-sectional data on 540 Type 1 diabetic patients, with a mean age of 40 years and diabetes duration of 22 years, from the EURODIAB Prospective Complications Study (PCS) were analysed. Retinopathy was assessed by centrally graded retinal photographs. Albumin excretion rate (AER) was used to define micro- and macroalbuminuria. CVD was defined as having physician diagnosed myocardial infarction (MI), stroke, coronary artery bypass graft (CABG) or angina, or Minnesota coded ischaemic electrocardiograms (ECGs).

RESULTS

Unadjusted, there was a positive relationship between sVCAM-1 and sE-selectin with nonproliferative and proliferative retinopathy, micro- and macroalbuminuria, and CVD. After adjustment for age, sex, duration of diabetes, systolic blood pressure (BP), LDL-cholesterol, fasting triglycerides (TGs), smoking, body mass index (BMI), and glycated haemoglobin, as well as other complications, the strongest significant associations were shown between sVCAM-1 and macroalbuminuria, with an odds ratio of 1.83 (1.33-2.53) for every 100 ng/ml increase in sVCAM-1.

CONCLUSIONS

In this large sample of Type 1 diabetic patients, it was shown that sVCAM-1 and sE-selectin have positive associations with retinopathy, albuminuria, and CVD. This suggests that adhesion molecules are important in the pathogenesis of vascular complications in Type 1 diabetes.

Homocysteine and other biochemical parameters in Type 2 diabetes mellitus with different diabetic duration or diabetic retinopathy

BACKGROUND

Cardiovascular risk-related markers in type 2 diabetes mellitus (DM) have not been well understood.

METHODS

Serum and urine samples for biochemical and immunologic analysis were collected from 204 normal subjects and 257 type 2 DM patients, the latter of which were further classified by different diabetic duration with or without retinopathy.

RESULTS

Glycosylated hemoglobin A1c, triglyceride, lipase, free fatty acid, albumin creatinine ratio (ACR), lactate dehydrogenase (LDH) and homocysteine were significantly increased in DM patients, whereas high density lipoprotein cholesterol and bilirubin were significantly decreased in DM patients, compared with normal subjects. Lipid profiles, ACR, bilirubin, uric acid, creatine kinase, and hsCRP were not changed in DM patients with different diabetic duration or diabetic retinopathy. Lactate dehydrogenase in DM patients with duration >20 years and homocysteine in patients with duration >10 years was significantly higher than those with duration <5 years. Homocysteine was significantly increased in DM patients with retinopathy, compared with DM patients without retinopathy.

CONCLUSION

The increased triglyceride, lipase, free fatty acid, albumin creatinine ratio, lactate dehydrogenase and homocysteine as well as decreased high density lipoprotein cholesterol and anti-oxidative bilirubin in DM patients should be cautious and considered as risks for increasing DM complication. Homocysteine might be associated with longer diabetic duration and microvascular complication of retinopathy in diabetes.

Increased serum levels of the specific advanced glycation end product methylglyoxal-derived hydroimidazolone are associated with retinopathy in patients with type 2 diabetes mellitus

Advanced glycation end products (AGEs) are thought to play a major pathogenic role in diabetic retinopathy. The most important AGE is unknown, but as increased serum methylglyoxal-derived hydroimidazolone has been demonstrated in patients with type 2 diabetes mellitus, the aim of the present study was to elucidate possible associations between serum levels of hydroimidazolone and retinopathy in patients with type 2 diabetes mellitus. We recruited 227 patients with type 2 diabetes mellitus and retinopathy ranging from none to proliferative. Level of retinopathy was determined from 7 standard field stereo photographs per eye according to the Early Treatment Diabetic Retinopathy Study. The patients were 66 +/- 11 years old, with a known diabetes duration of 14 +/- 9 years. Serum levels of hydroimidazolone were determined with a competitive immunoassay. Serum levels of hydroimidazolone were increased in nonproliferative (median, 4.50 U/mL; interquartile range, 3.69-5.77 U/mL) and proliferative retinopathy (median, 4.88 U/mL; interquartile range, 3.70-6.52 U/mL) compared with patients without retinopathy (median, 4.02 U/mL; interquartile range, 3.47-4.88 U/mL) (P = .008 and .002, respectively). There was no association between hydroimidazolone and hemoglobin A1c (r = 0.04, P = .57). In addition, patients with proliferative retinopathy and a relatively short known duration of diabetes, that is, less than the median of 14 years, had increased serum levels of hydroimidazolone (median, 6.91 U/mL; interquartile range, 4.70-8.91 U/mL) compared with those with nonproliferative retinopathy (median, 4.34; interquartile range, 3.86-5.53U/mL, P = .015). Serum levels of hydroimidazolone are increased in type 2 diabetic patients with retinopathy. This association is independent of hitherto known associated factors, such as hemoglobin A1c.

Urinary creatinine concentration is inversely related to glycaemic control and the presence of some diabetic complications in patients with newly diagnosed Type 2 diabetes

BACKGROUND

The ratio between urinary albumin concentration (UAC) and urinary creatinine concentration (UCC) is widely used to estimate renal involvement. We examined how UAC and UCC associate with each other, with other risk factors, and with diabetic complications in a population-based sample of Type 2 diabetic patients.

METHODS

A freshly voided morning urine specimen was provided by 1,284 consecutive, newly diagnosed diabetic patients aged 40 years or over in general practice. Albumin was measured by a polyethyleneglycol radioimmunoassay and creatinine by a modified Jaffe method.

RESULTS

In a multivariate model including UAC, UCC, age, sex, HbA1c, and urinary glucose concentration, UAC increased with both age (P=.042) and HbA1c (P=.014), while UCC decreased (P<.001 and P<.001, respectively). In two regression models, the prevalence of diabetic retinopathy (P<.001) and relatively high resting heart rate (P<.001) increased with increasing UAC but decreased with increasing UCC (P=.002 and P=.005, respectively).

CONCLUSION

The use of albumin/creatinine ratio (ACR) may introduce bias of unpredictable size and direction in comparisons of ACR with variables that are associated with UCC in their own right. In daily clinical practice, renal involvement in the individual patient can be estimated reliably with UAC or ACR measured in a freshly voided morning urine specimen, especially when considered together. However, the associations of the combined measure ACR should be interpreted with great caution in clinical and epidemiological research.

[Selected immunologic and biochemical risk factors of the retinopathy and nephropathy development in children with diabetes mellitus type 1]

INTRODUCTION

Despite that numerous investigations on the nature of diabetic microangiopathy were carried out, its pathomechanism remains unclear.

OBJECTIVE

The aim of the study was to analyze the relation between early diabetic microangiopathy and the proinflammatory cytokines, NAG and its A and B isoforms in blood and urine in children diagnosed with diabetes mellitus type 1.

MATERIAL AND METHODS

The study was carried out on the group of 56 children with diabetes mellitus 1 (age 13.6+/-3.74) and 35 healthy children selected as the controls. All the patients had 24 hrs albuminuria, HbA1c, C-peptide as well as the NAG enzyme and its A and B isoforms serum and urine activities measured. Additionally, all the children had TNF-a and IL6 level in serum measured. Each patient had 24 hrs blood pressure monitored and underwent ophthalmologic examination.

RESULTS

Children with long-standing diabetes mellitus and retinopathy (group 1, n=15) were older and were characterized by a statistically significant longer duration of the disease and higher HbA1c level in comparison with the patients who presented with no sign of diabetic retinopathy (group 2, n=41). In the group 1 statistically significant higher TNF-alpha serum level (p=0.01), NAG (p=0.002) and its isoforms A (p=0.007) and B (p=0.001) urine activities were measured in relation to the group 2. Additionally the level of IL-6 and NAG and its isoforms A and B serum activities were higher in group 1 than in group 2, however the differences were of no statistical significance. Moreover the children from group 2 in comparison with the healthy controls showed statistically significant higher TNF-alpha serum activity (p=0.016) and NAG (p<0.001) and its A (p<0.001) and B (p<0.001) isoforms both serum and urine activities.

CONCLUSIONS

The occurrence of the detectable serum TNF-alpha activity in children with diabetes mellitus type 1 showing no sign of diabetic retinopathy and nephropathy and no microalbuminuria with the concomitant increase of NAG and its isoforms serum and urine activities might point toward prompt occurrence of these changes in the eye and the kidneys.

Erytrocyte membrane anionic charge in type 2 diabetic patients with retinopathy

BACKGROUND

The Steno hypothesis states that changes in basement membrane anionic charge leads to diabetic microvascular complications. In diabetic nephropathy, loss of basement membrane glycosaminoglycans and the association between glomerular basement membrane heparan sulphate and proteinuria has been documented. A correlation between erythrocyte surface and the glomerular capillary wall charges has also been observed. The aim of this study is to evaluate the relationship between retinopathy and erythrocyte anionic charge and urinary glycosaminoglycan excretion in type 2 diabetic patients.

METHODS

49 subjects (58 +/- 7 yrs, M/F 27/22) with type 2 diabetes with proliferative retinopathy (n = 13), nonproliferative retinopathy (n = 13) and without retinopathy (n = 23) were included in the study. 38 healthy subjects were selected as control group (57 +/- 5 yrs, M/F 19/19). Erythrocyte anionic charge (EAC) was determined by the binding of the cationic dye, alcian blue. Urinary glycosaminoglycan and microalbumin excretion were measured.

RESULTS

EAC was significantly decreased in diabetic patients with retinopathy (255 +/- 30 ng alcian blue/10(6) RBC, 312 +/- 30 ng alcian blue/10(6) RBC for diabetic and control groups respectively, p < 0.001). We did not observe an association between urinary GAG and microalbumin excretion and diabetic retinopathy. EAC is found to be negatively correlated with microalbuminuria in all groups.

CONCLUSIONS

We conclude that type 2 diabetic patients with low erythrocyte anionic charge are associated with diabetic retinopathy. Reduction of negative charge of basement membranes may indicate general changes in microvasculature rather than retinopathy. More prospective and large studies needs to clarify the role of glycosaminoglycans on progression of retinopathy in type 2 diabetic patients.

Diabetic microvasculopathy: the renal-retinal link

Manifestations of diabetic microvasculopathy are protean. Graded increases in the severity are recognised in both nephropathy and retinopathy. This study was undertaken with 100 patients of type 2 diabetes mellitus to evaluate how far these graded increments could be linked at each stage and in each patient. The renal parameters studied were the various accepted levels of albuminuria; the retinopathy parameters ranged from normal retina to severe proliferative stages. Corresponding grades were proposed and altered, if required, to reach the best possible correlation. The correlation was attempted though the common link of mean glomerular filtation rates at each level and the concordance of either parameter grade in an individual patient. The correlations of the mean glomerular filtration rate for all propositions of severity were significant. However, there was significant variability of the parameters in an individual patient. This was more with less severe grades but diminished with increased duration. The predictive value of one lesion for the other was low in cases with shorter duration and less severe grades. Probably, shorter duration patients have an interplay of both genetic factors and the assault of the risk factors while in longer duration patients the cumulative risk exposure play the dominant role.

The long-term renal and retinal outcome of childhood-onset Type 1 diabetes

AIMS

To quantify the influence of childhood onset on long-term renal and retinal outcome in Type 1 diabetes.

METHODS

We used a population-based diabetes register to identify all Type 1 patients diagnosed before age 15 from 1960 to 1982 and resident in a defined catchment area in 1999. Those diagnosed before age 5, aged 5-9 and 10-14 years were compared with a reference group diagnosed at age 21-25 years over the same period.

RESULTS

Compared with adult-onset controls, proteinuria occurred earlier (P = 0.02) and nephropathy outcome was worse (P = 0.008) in childhood-onset diabetes. The risk of developing microalbuminuria was greater in childhood-onset diabetes: odds ratio 2.6 (95% confidence interval 1.4-4.9, P = 0.003). The relative risk of established nephropathy was 3.8 (1.5-9.4, P = 0.005) with childhood onset. The number developing background retinopathy did not differ with age at onset but younger onset patients were more likely to need laser treatment: relative risk 2.1 (1.1-3.8, P = 0.02). This maintained visual outcome which was not significantly different between the various age at onset groups.

CONCLUSIONS

Patients with onset of Type 1 diabetes before age 15 have substantially worse renal outcome and require more laser treatment than adult-onset patients. Differences between those with onset before age 5, onset at 5-9 and 10-14 years are small compared with the difference between childhood onset and adult onset. Events in the teenage years therefore appear to have a major adverse effect on the risk of developing long-term microvascular complications.

The relationship between the circulating IGF system and the presence of retinopathy in Type 1 diabetic patients

BACKGROUND

Patients with proliferative diabetic retinopathy (PDR) have increased vitreous levels of insulin-like growth factor (IGF)-I, IGF-II and IGF binding proteins (IGFBPs). This accumulation is probably caused by increased leakiness of the blood-retina barrier and influx of circulating IGFs and IGFBPs. To date, interest has focused on the role of circulating total IGF-I in the development of PDR, and there are only sparse data on circulating levels of free IGF-I and IGFBPs.

METHODS

We compared fasting serum samples from matched groups of Type 1 diabetic patients with no retinopathy (n = 29), non-PDR (n = 13) and PDR (n = 16). We also included matched controls (n = 26). Serum was analysed for free and total IGF-I and -II, free plus dissociable IGF-I, IGFBP-1, -2 and -3, IGFBP-1-bound IGF-I as well as IGFBP-3 proteolysis.

RESULTS

When compared with controls, diabetic patients (n = 58) showed reduced (P < 0.0005) levels of free and total IGFs, free plus dissociable IGF-I and IGFBP-3, whereas levels of IGFBP-1, IGFBP-1-bound IGF-I and IGFBP-2 were elevated. IGFBP-3 proteolysis remained unaltered. When comparing diabetic patients with different degrees of retinopathy, IGFBP-2 and IGFBP-1-bound IGF-I were the only parameters that differed significantly. Patients with retinopathy (non-PDR as well as PDR) had elevated IGFBP-2 (P < 0.03) and reduced IGFBP-1-bound IGF-I (P < 0.03), when compared with patients without retinopathy. Noteworthy, both parameters correlated (0.11 < r2 < 0.14, P < 0.02) with the severity of retinopathy.

CONCLUSION

Our study gives no evidence of a direct role of circulating free IGF-I in the development of PDR, whereas IGFBP-2 and IGFBP-1-bound IGF-I showed a relationship with the degree of retinopathy. However, further investigations are needed in order to clarify the basis and clinical relevance of this finding.

Increased urinary albumin excretion and its associations in the WHO Multinational Study of Vascular Disease in Diabetes

AIM/HYPOTHESIS

We aimed to determine variations in the prevalence of increased urinary albumin excretion, associated risk factors and complications in patients with diabetes participating in the WHO Multinational Study of Vascular Disease in Diabetes follow-up.

METHODS

Urinary albumin to urinary creatinine ratios were measured centrally in 2,033 of the 2,550 (79.7%) re-examined patients from eight centres in seven countries and the frequency of microalbuminuria and macroalbuminuria and their associations with risk factors and complications were examined.

RESULTS

Macroalbuminuria prevalence (overall 15.6%) varied tenfold (3-37%) among centres, was higher in American Indian and Asian centres and not clearly related to type of diabetes. Microalbuminuria (overall 19.7 %) varied less (12-31%). Increased albumin excretion was related overall to baseline fasting plasma glucose in the pooled group in whom it was measured and to increased arterial pressure, insulin use, coronary heart disease, lower extremity amputation, retinopathy and stroke in most centres.

CONCLUSION/INTERPRETATION

Centres varied widely in the prevalence of increased albumin excretion but associations with risk factors and vascular complications were generally similar in most centres and in both major types of diabetes with ethnic and genetic differences probably contributing.

Diabetic retinopathy in newly diagnosed middle-aged and elderly diabetic patients. Prevalence and interrelationship with microalbuminuria and triglycerides

BACKGROUND

The exact role of factors such as serum lipids, body mass index and (micro-)albuminuria as possible determinants of diabetic retinopathy remains to be determined. We have scrutinized the prevalence of diabetic retinopathy and its concomitants in terms of risk factors and other diabetic complications in newly diagnosed diabetic patients.

METHODS

A population-based sample of 1,251 newly diagnosed diabetic patients aged 40 years or over was established in general practice. Median age was 65.3 years. Funduscopy was performed by practising ophthalmologists. Blood and urine analyses were centralised.

RESULTS

The overall prevalence of diabetic retinopathy was 5.0%. Only three patients had proliferative diabetic retinopathy. As expected, diabetic retinopathy and renal involvement, as expressed by the urinary albumin/creatinine ratio. were strongly positively associated. An intriguing finding was that of an inverse relationship between fasting triglycerides and diabetic retinopathy, an association that proved to be confined to microalbuminuric patients. An inverse association between body mass index and diabetic retinopathy was found only univariately.

CONCLUSION

The low prevalence of diabetic retinopathy cannot be explained by the screening method alone, but rather by early detection of diabetes in a non-selective patient sample. It seems that renal involvement modifies the expected relationship between diabetic retinopathy and triglycerides, but a pathophysiological mechanism is not available.

Follow-up of plasma semicarbazide-sensitive amine oxidase activity and retinopathy in Type 2 diabetes mellitus

Plasma activity of the enzyme semicarbazide-sensitive amine oxidase (SSAO) is high in diabetes. Production of angiotoxic substances (an aldehyde, hydrogen peroxide, and ammonia) in vessel walls is catalysed by SSAO, suggesting a role for SSAO in the development of complications of diabetes. The objective of the present study was to follow up plasma SSAO activity (measured radiometrically), HbA(1c) (using ion exchange chromatography), and retinopathy (by fundus photography) after 2.8 years, in 34 patients with Type 2 diabetes. We also measured urinary levels of an SSAO substrate, methylamine, by fluorometric high-performance liquid chromatography (HPLC). As at baseline, plasma SSAO activity was now higher in subjects with retinopathy (mean 19.5) than in subjects without retinopathy (mean 16.0), 95% confidence interval (CI) for difference 0.6-6.3 nmol benzylamine ml(-1) plasma h(-1). SSAO activity had not changed significantly since baseline, mean difference -1.65 and 95% CI for difference -3.76 to 0.46 nmol benzylamine ml(-1) plasma h(-1). Mean HbA(1c) level remained higher for patients with retinopathy (now 7.9%) compared to those without retinopathy (6.1%), 95% CI for difference 0.6-3.0%. Comparing baseline and the present study, retinopathy was nonproliferative; level had worsened for five and improved for two patients. Urinary methylamine/creatinine ratio was lower in the group of patients with retinopathy (mean 0.99) than in those without retinopathy (mean 1.78), 95% CI for difference 0.1-1.5 microg mg(-1). The results of the present study are compatible with a role for SSAO in the development of diabetic retinopathy.

Heart rate elevation and diabetic retinopathy in patients with type 2 diabetes mellitus and normoalbuminuria

To investigate the role of heart rate (HR) and blood pressure (BP) for diabetic retinopathy, 24-h ambulatory HR and BP were monitored for 162 in patients with type 2 diabetes and normoalbuminuria. The fundus was assessed as no retinopathy, simple diabetic retinopathy (SDR) and proliferative retinopathy (PDR). Comparing the highest with the lowest quartile of diabetic duration, the relative risk for retinopathy was 9.3 and for nocturnal HR, it was 3.6. Comparison among three retinopathy groups (no retinopathy, group 1, n=122; SDR, group 2, n=24; Pre-PDR or PDR, group 3, n=16) showed that 24-h and nocturnal HR were significantly higher in group 3 (80+/-9 and 71+/-9 beats per min) than in group 2 (73+/-8 and 64+/-8) and group 1 (72+/-7 and 60+/-7). In multiple logistic analysis, the odds ratio of diabetic duration and nocturnal HR to the existence of retinopathy was 1.17 (95% CI, 1.10-1.25, P=0.00001) and 1.11 (95% CI, 1.05-1.17, P=0.0002). We concluded that diabetic retinopathy is related to diabetic duration and high heart rate in type 2 diabetes mellitus with normoalbuminuria. Heart rate elevation may be a predictor of advanced retinopathy.

Clinical usefulness of measuring urinary polyol excretion by gas-chromatography/mass-spectrometry in type 2 diabetes to assess polyol pathway activity

INTRODUCTION

Decreased myo-inositol levels and increased activity of the polyol pathway have been proposed to play a role in causing diabetic microvascular complications. There are few clinical methods for examining the activity of the polyol pathway in diabetic patients. We assessed the effect of changes in glycemic control on polyol pathway activity by measuring urinary polyol excretion.

MATERIALS AND METHODS

Gas-chromatography/mass-spectrometry (GC/MS) was used to assess the urinary excretion of glucose and polyols (myo-inositol, sorbitol, and fructose) in 50 patients who had type 2 diabetes without nephropathy and 20 healthy subjects.

RESULTS

In the diabetic patients with poor glycemic control, urinary sorbitol levels were significantly increased and urinary myo-inositol excretion was approximately 6.5-fold higher than in healthy controls (33.0+/-6.5 vs 221.7+/-45.9 mg/day, mean+/-SE, P<0.01). During strict glycemic control, some patients (Group A) showed simultaneous disappearance of glucosuria and normalization of the urinary excretion of myo-inositol (<50 mg/day) and, while others (Group B) showed delayed normalization of urinary myo-inositol excretion. Group B showed significantly higher urinary myo-inositol, sorbitol, and fructose excretion than Group A at the time of disappearance of glucosuria. These findings suggest that patients in Group B may have increased polyol pathway activity.

CONCLUSION

Even though short-term strict glycemic regulations were established in long-standing hyperglycemic diabetic patients, to normalize the once-exaggerated polyol pathway activities, it was essential to maintain glucosuria-free conditions for some period. Quantitation of urinary polyols using GC/MS appears to be a clinically useful method for assessing polyol pathway activity.

Do urinary levels of vascular endothelial growth factor predict proliferative retinopathy?

PURPOSE

Vascular endothelial growth factor (VEGF) is elevated in the vitreous of patients with proliferative retinopathies (PR). Angiogenic factors like VEGF are elevated in the urine of subjects with cancers, including those distant from the genitourinary tract. We hypothesized that local increases in VEGF in the vitreous would be reflected in the urine of subjects with PR.

METHODS

Urine samples were collected from adults with absent, mild, or severe (requiring laser photocoagulation) PR. VEGF was measured by enzyme linked immunosorbent assay.

RESULTS

Of 42 subjects, 16 had no PR and 26 had PR (8 mild, 18 severe). Thirty subjects had diabetes mellitus; 24 of these had PR. Subjects with PR were older than controls. Subjects with PR tended to have higher urinary VEGF (median 123 pg/ml Cr, range 3--1738) than controls without PR (median 93 pg/ml Cr, range 2--200) (p = 0.08). None of 16 controls, but 11/15 subjects with PR had >200 mg VEGF/mg Cr (p = 0.003), yielding high specificity (100%), but poor sensitivity (42%) of elevated urinary VEGF for PR. Urinary VEGF was also modestly correlated with urinary protein excretion (r(2 ) = 0.23). Correction of VEGF values for urinary protein abrogated any correlation with PR.

CONCLUSIONS

Urinary levels of VEGF are associated with PR, but this relationship may be caused by concurrent renal diseases that result in proteinuria and/or renal VEGF production. The insensitivity of the association may preclude its use in screening to avoid eye examinations.

[Clinical value of urinary excretion of N-acetyl-beta-glucosaminidase in diabetic retinopathy]

PURPOSE

To test N-acetyl-beta-glucosaminidase (NAG) urinary excretion, early renal damage biochemical marker, in patients with non-insulin-dependent diabetes mellitus grouped according to the degree of retinopathy, establishing its relationships to retinal involvement.

METHODS

We make a prospective study of 144 type 2 diabetic patients and 94 healthy subjects. We realized an ocular exploration that included fluorescein angiography and a biochemical study that included the determination of NAG urinary excretion in all of them. The patients were grouped depending on their retinal disease. 76 subjects without retinal abnormalities (40 men and 36 women), 30 with early nonproliferative diabetic retinopathy (13 men and 17 women) and 21 subjects with proliferative diabetic retinopathy (10 men and 11 women). Results were analyzed by using statistical analyses.

RESULTS

Our results showed that there exist an increase in the urinary excretion of NAG according to the degree of diabetic retinopathy advance. We also highlight the biggest urinary excretion of NAG in the diabetic patients without retinal involvement regarding healthy subjects.

CONCLUSION

There is a parallelism between renal and retinal complications in type 2 diabetes mellitus as other authors had demonstrated previously for the type 1 diabetes mellitus.

Residual beta-cell function and microvascular complications in type 1 diabetic patients

To determine the influence of residual beta-cell function on retinopathy and microalbuminuria we measured basal C-peptide in 50 type 1 diabetic outpatients aged 24.96 +/- 7.14 years, with a duration of diabetes of 9.1 +/- 6.2 years. Forty-three patients (86%) with low C-peptide (<0.74 ng/ml) had longer duration of diabetes than 7 patients (14%) with high C-peptide (> or =0.74 ng/ml) (9 (2-34) vs 3 (1-10) years, P = 0.01) and a tendency to high glycated hemoglobin (HBA1) (8.8 (6-17.9) vs 7.7 (6.9-8.7)%, P = 0. 08). Nine patients (18%) had microalbuminuria (two out of three overnight urine samples with an albumin excretion rate (AER) > or =20 and <200 microg/min) and 13 (26%) had background retinopathy. No association was found between low C-peptide, microalbuminuria and retinopathy and no difference in basal C-peptide was observed between microalbuminuric and normoalbuminuric patients (0.4 +/- 0.5 vs 0.19 +/- 0.22 ng/ml, P = 0.61) and between patients with or without retinopathy (0.4 +/- 0.6 vs 0.2 +/- 0.3 ng/ml, P = 0.43). Multiple regression analysis showed that duration of diabetes (r = 0. 30, r2 = 0.09, P = 0.031) followed by HBA1 (r = 0.41, r2 = 0.17, P = 0.01) influenced basal C-peptide, and this duration of diabetes was the only variable affecting AER (r = 0.40, r2 = 0.16, P = 0.004). In our sample of type 1 diabetic patients residual ss-cell function was not associated with microalbuminuria or retinopathy.

Polymorphisms of angiotensin-converting enzyme and angiotensinogen genes in type 2 diabetic sibships in relation to albumin excretion rate

Familial clustering of altered albumin excretion and nephropathy risk has been described in both type 1 and type 2 diabetes; moreover, an association of micro-macroalbuminuria and diabetic retinopathy has been recently reported in a large number of white families with type 2 diabetes. Conflicting reports, mainly comparing affected with unaffected unrelated subjects, have suggested a possible role of some genotypes of the renin-angiotensin system in conferring nephropathy risk in type 2 diabetes. To examine the role of genetic factors in influencing albuminuria in families, we studied the relation of angiotensin-converting enzymes (ACE) and angiotensinogen (AGN) genotypes with albumin excretion rate in a population of affected siblings of type 2 diabetic probands. We determined ACE insertion/deletion polymorphism and two polymorphisms of the AGN gene (T174M and M235T) in 160 families with at least one affected member. Defining proband as the patient with the longest known duration of diabetes, we compared the allelic distribution in diabetic probands with and without altered albumin excretion and in their siblings. Allelic distribution of these polymorphisms was similar in the two groups of probands, as well as in their siblings. Identity-by-State (IBS) analysis showed a link between AGN locus and arterial hypertension in these siblings, which was independent from the degree of renal involvement. Thus, our findings suggest that in white families with type 2 diabetes, there is no linkage between the degree of albumin excretion and ACE and AGN polymorphisms, whereas the latter is related to arterial hypertension, as previously found in patients without diabetes but with essential hypertension.

Elevated serum leptin concentrations in type 2 diabetic patients with microalbuminuria and macroalbuminuria

Leptin levels are elevated in end-stage renal disease, suggesting an impairment of renal leptin degradation. The present study aimed to determine whether leptin levels are also elevated in patients with earlier stages of renal disease, ie, microalbuminuric and macroalbuminuric nephropathy. A total of 60 subjects were assigned to two study groups. Group A contained 10 type 2 diabetics with macroalbuminuria, 10 type 2 diabetics with normoalbuminuria, and 10 healthy control subjects. Group B contained 10 type 2 diabetics with microalbuminuria, 10 type 2 diabetics with normoalbuminuria, and 10 healthy controls. The subgroups of both study groups were matched for sex and body fatness. In group A, macroalbuminuric diabetic patients had higher serum leptin levels than the normoalbuminuric diabetics (11.90 +/- 2.98 v 4.13 +/- 0.92 ng/mL, P < .002) and control subjects (4.78 +/- 1.37 ng/mL, P < .006). In group B, microalbuminuric diabetics had higher serum leptin levels than the normoalbuminuric diabetics (21.16 +/- 5.80 v8.74 +/- 1.89 ng/mL, P < .04) and control subjects (10.06 + 3.00 ng/mL, P < .06). In both groups A and B, creatinine clearance was inversely correlated with the serum leptin level after adjusting for body fat. In conclusion, serum leptin levels are elevated in type 2 diabetic patients with microalbuminuria and macroalbuminuria, suggesting that renal leptin degradation is already impaired in the early stages of renal disease.

Microalbuminuria is closely related to diabetic macroangiopathy

To investigate whether urinary excretion of transferrin (uTf) and albumin (uAlb) is related to diabetic macroangiopathy, we compared the levels of uTf and uAlb between ischemic heart disease (IHD) group and non-IHD group in patients with non-insulin-dependent diabetes mellitus. The patients (n = 102) without macroproteinuria were enrolled in the present study. Firstly, we divided the subjects into the two groups, IHD group (n = 16) and non-IHD group (n = 86), according to findings of ischemic changes on electrocardiogram. The levels of uTf and uAlb in IHD group were 3.9 +/- 0.9 and 40.6 +/- 9.7 (mean +/- S.E.M.) mg/g Creatinine, respectively. These values were significantly (P < 0.01) higher than those of non-IHD group (1.8 +/- 0.2 for uTf and 19.6 +/- 1.8 for uAlb). There was no significance in the levels of HbA1c, blood pressure, plasma lipids, and diabetic duration between the two groups. Secondly, we divided the subjects by the levels of uTf and uAlb. The frequency of IHD in the group (n = 22, 36.4%) with microalbuminuria and microtransferrinuria was significantly (P <0.03) higher than those (n = 38, 10.5%) with normoalbuninuria and microtransferrinuria, and also significantly (P < 0.02) higher than those (n = 42, 9.5%) with normoalbuminuria and normotransferrinuria. We concluded that the measurement of uAlb is important when approaching diabetic macroangiopathy.