Prevalence of complications in IDDM by sex and duration. Pittsburgh Epidemiology of Diabetes Complications Study II

Early risk stratification in pediatric type 1 diabetes

In the late 1980s all Danish children with type 1 diabetes were invited for a nationwide evaluation of glycemic control. Approximately 75% (n = 720) participated and have later been referred to as The Danish Cohort of Pediatric Diabetes 1987 (DCPD1987). The results were surprisingly poor glycemic control among these young patients which lead to a great emphasis on glycemic control in the Danish Pediatric Departments. In 1995 the participants were invited for yet another evaluation but this time with main focus on early signs of microvascular complications - 339 participated. The mean HbA1c had remained at high levels (9.6%) and 60% of the participants had some level of Diabetic Retinopathy (DR). However, as the patients with DR mostly had the very milder forms it was believed that stricter glycemic control would reverse or at least stop progression of the disease in accordance with results from the large intervention study DCCT. This was investigated further at follow-up in 2011. The first study in the present thesis aimed to describe the 16-year incidence, progression and regression of DR in 185 participants from the DCPD1987 cohort. The 16-year incidence of proliferative retinopathy (PDR), 2-step progression and regression of DR was 31.0, 64.4, and 0.0%, respectively. As expected, the participants with PDR at follow-up had significantly higher HbA1c-values at both baseline and follow-up than those without PDR. However; a significantly larger decrease in HbA1c was also observed in the group with PDR over the study period, which in accordance with DCCT should have prevented the development of PDR to some extent. A surprisingly high incidence of proliferative retinopathy amongst young patients with type 1 diabetes in Denmark was found despite improvements in HbA1c over time. The improvement in HbA1c was either too small or happened too late. This study highlights that sight-threatening diabetic retinopathy remain a major concern in type 1 diabetes and the importance of early glycemic control. Identifying high-risk patients at a very early stage is not only desired for prevention of diabetic retinopathy - neuropathy and nephropathy similarly remain frequent in type 1 diabetes. Early risk stratification will allow for timely implementation of effective interventions and for individualized screening and diabetes care. The second and third studies of this thesis provide the longest prospective studies to date on both retinal vessel calibers and retinal fractal dimensions and their predictive value on diabetic microvascular complications. Semi-automated computer software has been developed to measure smaller changes in the retinal vessels on retinal photographs. Two of the first parameters to be reliably estimated by these programs were retinal vessel calibers and retinal vascular fractal dimensions (a quantitative measure on vascular complexity). There is very limited knowledge on their predictive value on diabetic complications thus far. In the second and third study, a consistent relation between narrower retinal arteriolar calibers, wider retinal venular calibers, lower fractal dimensions and the 16-year incidences of diabetic neuropathy, nephropathy and proliferative retinopathy was found. This has never been shown before. The results on vessel analyzes provides indications of a common pathogenic pathway for diabetic microvascular complications and therefore a possibility of universal risk estimation for development of neuropathy, nephropathy and retinopathy in type 1 diabetes.

The haptoglobin 1 allele correlates with white matter hyperintensities in middle-aged adults with type 1 diabetes

Although the haptoglobin (Hp) 1-1 genotype is associated with a lower coronary artery disease (CAD) risk in diabetes, we recently reported an increased stroke incidence in type 1 diabetes with Hp 1-1. We, thus, evaluated differences in earlier brain vascular abnormality markers by Hp using neuroimaging. Neuroimaging was completed in 94 participants of the Pittsburgh Epidemiology of Diabetes Complications study with Hp genotyping available (mean age, 49; duration, 41 years). White matter hyperintensities (WMH) volume, lacunar infarcts, and gray matter atrophy were quantified. Sixteen percent were homozygous for Hp 1 and 43% for Hp 2. A significant trend toward increased WMH was observed with greater duration and the number of Hp 1 alleles. Associations were strongest for the interhemispheric connecting fibers of the corpus callosum. Allowing for duration, sex, waist-to-hip ratio, HbA1c, systolic blood pressure, and lipids in models with backward elimination, results were similar. No significant differences by Hp were noted for atrophy or lacunar infarcts. Consistent with its direct association with stroke, the Hp 1-1 genotype is associated with higher WMH in this population. Further, including mechanistic, studies on the role of the Hp genotype in cerebrovascular disease and the implications for worsening cognitive function are needed.

End-stage renal disease and survival in people with diabetes: a national database linkage study

BACKGROUND

Increasing prevalence of diabetes worldwide is projected to lead to an increase in patients with end-stage renal disease (ESRD) requiring renal replacement therapy (RRT).

AIM

To provide contemporary estimates of the prevalence of ESRD and requirement for RRT among people with diabetes in a nationwide study and to report associated survival.

METHODS

Data were extracted and linked from three national databases: Scottish Renal Registry, Scottish Care Initiative-Diabetes Collaboration and National Records of Scotland death data. Survival analyses were modelled with Cox regression.

RESULTS

Point prevalence of chronic kidney disease (CKD)5 in 2008 was 1.63% of 19 414 people with type 1 diabetes (T1DM) compared with 0.58% of 167 871 people with type 2 diabetes (T2DM) (odds ratio for DM type 0.97, P = 0.77, on adjustment for duration. Although 83% of those with T1DM and CKD5 and 61% of those with T2DM and CKD5 were receiving RRT, there was no difference when adjusted for age, sex and DM duration (odds ratio for DM type 0.83, P = 0.432). Diabetic nephropathy was the primary renal diagnosis in 91% of people with T1DM and 58% of people with T2DM on RRT. Median survival time from initiation of RRT was 3.84 years (95% CI 2.77, 4.62) in T1DM and 2.16 years (95% CI: 1.92, 2.38) in T2DM.

CONCLUSION

Considerable numbers of patients with diabetes continue to progress to CKD5 and RRT. Almost half of all RRT cases in T2DM are considered to be due to conditions other than diabetic nephropathy. Median survival time for people with diabetes from initiation of RRT remains poor. These prevalence data are important for future resource planning.

Serum amyloid a truncations in type 2 diabetes mellitus

Serum Amyloid A (SAA) is an acute phase protein complex consisting of several abundant isoforms. The N- terminus of SAA is critical to its function in amyloid formation. SAA is frequently truncated, either missing an arginine or an arginine-serine dipeptide, resulting in isoforms that may influence the capacity to form amyloid. However, the relative abundance of truncated SAA in diabetes and chronic kidney disease is not known.

The effect of sex on humanin levels in healthy adults and patients with uncomplicated type 1 diabetes mellitus

Diabetes mellitus (DM) is associated with a loss of renal and vascular protection in women compared with men, but the responsible mechanisms are unclear. Recent experimental work implicated humanin (HN) as a novel cytoprotective hormone in DM. Our goal was to measure sex-related differences in HN levels in uncomplicated type 1 DM patients (T1D) and healthy controls (HC), as well as the interaction between HN, circulating neurohormones, and vascular function. Plasma HN, cGMP and aldosterone, blood pressure (BP), glomerular filtration rate, and effective renal plasma flow (inulin and para-aminohippurate) were measured in HC (11 men, 10 women) and T1D (23 men and 18 women) during clamped euglycemia (4-6 mmol·L(-1)). Plasma HN levels were generally lower in HC men by comparison with the women, but the differences were not statistically significant. In contrast, levels in the T1D men were higher compared with the T1D women (p = 0.026) and HC men (p < 0.0001). In the HC men, but not the women, HN correlated negatively with BP, but not with renal function, cGMP, or aldosterone. In the T1D men, HN negatively correlated with plasma cGMP. In the T1D women, HN did not correlate with neurohormones or vascular function. Future work should determine the role of HN in the pathogenesis of sex-related vascular function differences in DM.

[Peripheral arterial disease of the lower limbs in African diabetic patients: ultrasonography and determining factors]

INTRODUCTION

Diabetic peripheral arterial disease (PAD) of the lower limbs is underdiagnosed.

METHODOLOGY

This was a prospective study conducted over a six-month period from November 2012 to April 2013. A total of 308 diabetic patients were included from three diabetes centers in Abidjan (Ivory Coast).

AIM

To screen for PAD of the lower limbs in a diabetic population and to identify the determining factors.

RESULTS

Among the 308 patients, the ankle-brachial index (ABI) was<0.9 in 68 (22.07%) patients considered to have PAD; the ABI was>1.3 in 56 (18.2%) patients who had suspected mediacalcosis. The average age of the PAD patients was 60.2 years. Female gender predominated (55.9%). The mean duration of diabetes was 9.6 years: 97.1% type 2 diabetes. The other cardiovascular risk factors in this population were hypertension (58.8%) and dyslipidemia (40.9%). Smoking was present in 29.4% of patients and obesity in 23.9%. PAD of the lower limbs was mild in 46 patients (67.6%), moderate in 16 (23.5%) and severe in 6 (8.8%). Duplex Doppler commonly showed lesions of the tibial arteries. Determining factors of diabetic PAD of the lower limbs were hypertension (58.8% vs 36.6%; OR=2.46; 95% CI: 1.13-5.36; P=0.034) and dyslipidemia (40.9% vs 8.3%; OR=7.6; 95% CI: 2.31-25.08; P=0.0009). For mediacalcosis, male gender (71.5% vs 39.7; OR=0.26 95% CI/0.10-0.64. P=0.004) was the only factor identified.

CONCLUSION

Hypertension and dyslipidemia were predictive factors for diabetic PAD of the lower limbs in our African population.

Predicting major outcomes in type 1 diabetes: a model development and validation study

AIMS/HYPOTHESIS

Type 1 diabetes is associated with a higher risk of major vascular complications and death. A reliable method that predicted these outcomes early in the disease process would help in risk classification. We therefore developed such a prognostic model and quantified its performance in independent cohorts.

METHODS

Data were analysed from 1,973 participants with type 1 diabetes followed for 7 years in the EURODIAB Prospective Complications Study. Strong prognostic factors for major outcomes were combined in a Weibull regression model. The performance of the model was tested in three different prospective cohorts: the Pittsburgh Epidemiology of Diabetes Complications study (EDC, n = 554), the Finnish Diabetic Nephropathy study (FinnDiane, n = 2,999) and the Coronary Artery Calcification in Type 1 Diabetes study (CACTI, n = 580). Major outcomes included major CHD, stroke, end-stage renal failure, amputations, blindness and all-cause death.

RESULTS

A total of 95 EURODIAB patients with type 1 diabetes developed major outcomes during follow-up. Prognostic factors were age, HbA1c, WHR, albumin/creatinine ratio and HDL-cholesterol level. The discriminative ability of the model was adequate, with a concordance statistic (C-statistic) of 0.74. Discrimination was similar or even better in the independent cohorts, the C-statistics being: EDC, 0.79; FinnDiane, 0.82; and CACTI, 0.73.

CONCLUSIONS/INTERPRETATION

Our prognostic model, which uses easily accessible clinical features can discriminate between type 1 diabetes patients who have a good or a poor prognosis. Such a prognostic model may be helpful in clinical practice and for risk stratification in clinical trials.

Haptoglobin genotype and cerebrovascular disease incidence in type 1 diabetes

OBJECTIVE

We prospectively evaluated the haptoglobin (Hp)-stroke association in type 1 diabetes and hypothesized that despite increasing the risk of coronary artery disease, the presence of the Hp 2 allele would be associated with a lower incidence of stroke.

METHODS

Participants from the Epidemiology of Diabetes Complications study without prevalent stroke and Hp available were evaluated (n = 607; mean age 27.6 years and duration 19.3 years).

RESULTS

During 22 years of follow-up, stroke incidence did not differ by Hp genotype (p = 0.49). Restricting analyses to those diagnosed with diabetes ≥1965 (13% mortality vs 40% in the <1965 cohort) to diminish potential survival bias, the adjusted hazard ratio (HR) for Hp 1-1 was 3.08 (95% confidence interval (CI) = 0.81-11.77, p = 0.10). Further stratifying by hypertension prevalence, an increased stroke incidence was observed with Hp 1-1 only in those with hypertension (HR = 7.03, 95% CI = 1.42-34.89, p = 0.02).

CONCLUSION

Despite the protective effect against vascular diabetes complications, a borderline increased risk of stroke was observed with Hp 1-1 in type 1 diabetes. This mixed Hp effect on cardiovascular risk by outcome studied merits further investigation and cautions against the universal application of preventive therapies across all Hp genotypes.

Newly diagnosed diabetes mellitus patients presenting with proliferative diabetic retinopathy as an initial sign

AIM

To investigate the clinical features of newly diagnosed diabetes mellitus (NDM) patients showing proliferative diabetic retinopathy (PDR) as an initial sign.

METHODS

As a retrospective case series, the medical records of a total of four hundred and thirty-two patients who underwent a vitrectomy due to PDR were reviewed to find the subjects. Of 432 patients, six cases of NDM patients showing PDR as an initial sign were included and analyzed with their systemic and ocular features.

MAIN OUTCOME MEASURES

the systemic features and ocular features [preoperative and postoperative best corrected visual acuity (BCVA), intraoperative findings].

RESULTS

The mean onset age of visual symptoms was 36.3 years old. The mean serum insulin and C-peptide titer was below the normal range. The mean fasting plasma glucose was 178mg/dL and the mean postprandial 2h plasma glucose was 306mg/dL. The mean HbA1c at diagnosis was 11.02%. In all cases, an acute progressive fibrovascular proliferation was observed. Intraoperative retinal tears were found in three cases of six. The mean preoperative BCVA was +0.67±0.58 logMAR and the mean BCVA at postoperative 6 months was +0.20±0.30 logMAR.

CONCLUSION

All patients were considered to have latent autoimmune diabetes in adults (LADA). A rapid deterioration of kidney function as well as poor diabetic control status at diagnosis was observed in all six cases. The ocular features of the patients showed acute progressive fibrovascular proliferation and relatively favorable postoperative visual acuity.

Puberty as an accelerator for diabetes complications

Much is written about how difficult it is to deal with diabetes during adolescence, and rightly so. Less is understood as to how puberty may be an accelerator of vascular complications. With the increase in childhood diabetes, complication risks need to be revisited in relation to puberty and the secular increase in adiposity. Recent data suggest greater risk for severe vascular complications in those with diabetes during puberty, compared with young people who develop diabetes after puberty. It is also widely recognized that higher hemoglobin A1c (HbA1c) results are often seen during the pubertal period. This article will review complication outcomes in relation to puberty and examine mechanisms by which puberty may modify risk above glycemic exposure, and possible gender disparities in the risk of complications in the adolescent period.

Longitudinal prevalence of hypertension, proteinuria, and retinopathy in dogs with spontaneous diabetes mellitus

Background

The prevalence and progression of vascular complications of spontaneous diabetes mellitus (DM) in dogs have not been described.

Objectives

To investigate the effects of duration of disease, as estimated by time since DM diagnosis, and glycemic control on prevalence of systemic hypertension, proteinuria, and diabetic retinopathy in dogs with spontaneous DM.

Animals

Seventeen client‐owned dogs with spontaneous DM.

Methods

Prospective, longitudinal observational study. Dogs with DM of less than 1 year's duration were recruited and evaluated once every 6 months for 24 months. Recorded measures included indirect BP, urine albumin, protein and creatinine concentrations, serial blood glucose and serum fructosamine concentrations, ophthalmic examination, and a standardized behavioral questionnaire.

Results

Eleven dogs completed the 2‐year follow‐up period, during which the highest recorded prevalence of systolic and diastolic hypertension was 55 and 64%, respectively. Prevalence of microalbuminuria and elevated urine protein:creatinine ratio (UPC) ranged up to 73 and 55%, respectively. Prevalence of retinopathy ranged up to 20%. No significant effect of time since DM diagnosis or glycemic control was detected for any of the measures examined. Additionally, no significant associations between BP, urine albumin concentration, UPC and retinopathy were detected.

Conclusions and Clinical Relevance

With the exception of proteinuria, which was substantial in some cases, clinically deleterious diabetic vascular complications were not identified in dogs in this study.

The 16-year incidence, progression and regression of diabetic retinopathy in a young population-based Danish cohort with type 1 diabetes mellitus: The Danish cohort of pediatric diabetes 1987 (DCPD1987)

The aim was to investigate the long-term incidence of proliferative diabetic retinopathy (PDR), and progression and regression of diabetic retinopathy (DR) and associated risk factors in young Danish patients with Type 1 diabetes mellitus. In 1987-89, a pediatric cohort involving approximately 75 % of all children with Type 1 diabetes in Denmark <19 years of age was identified (n = 720). In 1995, 339 (47.1 %) were re-studied with retinopathy graded and all relevant diabetic parameters assessed. Of those, 185 (54.6 %) were evaluated again in 2011 for the same clinical parameters. All retinal images were graded using modified early treatment of DR study for 1995 and 2011. In 1995, mean age was 21.0 years and mean diabetes duration 13.5 years. The 16-year incidence of proliferative retinopathy, 2-step progression and 2-step regression of DR was 31.0, 64.4 and 0.0 %, respectively, while the incidence of DR was 95.1 %. In a multivariate logistic regression model, progression to PDR was significantly associated with 1995 HbA1c (OR 2.61 per 1 % increase, 95 % CI 1.85-3.68) and 1995 diastolic blood pressure (OR 1.79 per 10 mmHg increase, 95 % CI 1.04-3.07). Two-step progression of DR was associated with male gender (OR 2.37 vs. female, 95 % CI 1.07-5.27), 1995 HbA1c (OR 3.02 per 1 % increase, 95 % CI 2.04-4.48) and 1995 vibration perception threshold (OR 1.19 per 1 Volt increase, 95 % CI 1.02-1.40). In conclusion, one in three progressed to PDR and two in three had 2-step progression despite young age and increased awareness of the importance of metabolic control. After 30 years duration of diabetes, the presence of DR is almost universal.

Oral health behavior and HbA1c in Indian adults with type 2 diabetes

Prevention and treatment of oral diseases and diabetes require persistent daily self-care, as there is a mutual association between periodontitis severity and level of diabetes control. In this questionnaire study, we investigated oral health behavior, attitudes, and knowledge of diabetes-related factors among 500 Indian adults with type 2 diabetes mellitus. The questionnaire asked about oral self-care, dental visits, self-perceived problems, and knowledge of the relationship between diabetes and oral health. The most recent glycosylated hemoglobin (HbA1c) value was obtained from patient medical records. Overall, 22% of participants reported twice-daily toothbrushing; women were more likely than men to brush twice daily (P< 0.001). With respect to age and diabetes control, participants aged 35-44 years with good diabetes control had the highest rate of twice-daily brushing (P< 0.001). Oral self-care and use of dental services were poor among participants. The present results indicate that Indians with type 2 diabetes need further promotion of oral self-care and regular dental checkups to compensate for their increased risk of oral disease.

Frontal gray matter atrophy in middle aged adults with type 1 diabetes is independent of cardiovascular risk factors and diabetes complications

AIMS

To determine if regional gray matter volume (GMV) differences in middle-aged adults with and without type-1 diabetes (T1D) are localized in areas most vulnerable to aging, e.g. fronto-subcortical networks; and if these differences are explained by cardiovascular risk factors and diabetes complications.

METHODS

Regional GMV was computed using 3T MRI of 104 adults with a childhood onset of T1D (mean age: 49±7 and duration: 41±6years) and 151 adults without diabetes (mean age: 40±6). A Bonferroni threshold (n=45, p≤0.001) was applied to account for multiple between-group comparisons and analyses were repeated in an age- and gender-matched subset of participants with T1D and controls (n=44 in each group, mean age [SD] and range: 44.0, [4.3], 17.4 and 44.6 [4.3], 17.0, respectively).

RESULTS

Compared to controls, T1D patients had smaller GMV in the frontal lobe (6% to 19% smaller) and adjacent supramarginal and postcentral gyri (8% to 13% smaller). Between-group differences were independent of age, waist circumference, systolic blood pressure, fasting total cholesterol and smoking status and were similar in sensitivity analyses restricted to age- and gender-matched participants. Associations between GMV and diabetes complications were not significant.

CONCLUSIONS

These findings extend the notion of accelerated brain aging in T1D to middle-aged adults. The pathophysiology of frontal gray matter atrophy and its impact on future development of disability and dementia need further study, especially as middle-aged T1D patients progress to older age.

Gender, clamped hyperglycemia and arterial stiffness in patients with uncomplicated type 1 diabetes mellitus

BACKGROUND

Diabetes mellitus (DM) reduces female gender-mediated protection against the development of renal disease possibly through effects on hyperglycemia. Women with DM also exhibit increased arterial stiffness, which may promote renal disease progression. The mechanisms responsible for increased arterial stiffness in women and the possible role of acute changes in ambient glycemia remain unknown.

METHODS

Blood pressure, augmentation index (AIx), pulse wave velocity (PWV) and circulating mediators of the renin angiotensin system and nitric oxide (cGMP) were measured in men (n = 22) and women (n = 19) with uncomplicated type 1 DM under clamped euglycemic and hyperglycemic conditions.

RESULTS

At baseline, men exhibited higher levels of angiotensin II (p = 0.030) and lower cGMP levels (p = 0.004), higher systolic blood pressure (124 ± 2 versus 109 ± 2 mmHg, p < 0.0001) and pulse pressure (42 ± 2 versus 58 ± 2 beats per minute, p < 0.0001). For arterial stiffness, radial (-8.0 ± 2.6% versus +5.4 ± 3.7%, p < 0.0001) and carotid AIx (-4.7 ± 2.9 versus +12.5 ± 3.0, p < 0.0001) were lower in men versus women. In contrast, carotid-femoral PWV was similar in men and women (5.20 ± 0.30 versus 5.13 ± 0.17, respectively, p = 0.853). In response to clamped hyperglycemia, systolic blood pressure increased in women (109 ± 2 to 112 ± 2 mmHg, p = 0.005) but not men. Serum aldosterone increased and cGMP declined in women but not in men. Clamped hyperglycemia did not influence arterial stiffness in either group and radial and carotid AIx remained higher in women.

CONCLUSIONS

Arterial stiffness is higher in women with type 1 DM. This effect is not dependent on the effects of clamped hyperglycemia or neurohormonal activation.

The effect of sex on endothelial function responses to clamped hyperglycemia in type 1 diabetes

Although the female sex is associated with renal protection in non-diabetic nephropathy, men and women with type 1 diabetes mellitus (T1D) have a similar risk of developing nephropathy. As hyperglycemia is associated with exaggerated effects on blood pressure and renal hyperfiltration in women versus men with T1D, we examined the influence of clamped hyperglycemia on flow mediated vasodilatation (FMD) to determine if this parameter contributes to sex-related differences in the vascular function. After a controlled diet for seven days, blood pressure, ultrasound derived FMD and circulating renin angiotensin system mediators were measured in men (n=30) and women (n=28) with T1D during clamped euglycemia and hyperglycemia. Men and women were similar in pre-study dietary parameters, age, diabetes duration, body mass index, HbA1c, renal function and proteinuria. The systolic blood pressure (SBP) was higher in men during clamped euglycemia (121±2 vs. 108±2 mm Hg, P<0.0001) and hyperglycemia (121±2 vs. 111±2 mm Hg, P<0.0001), as were the circulating levels of angiotensin II (P<0.05). SBP increased in response to hyperglycemia in women but not in men. Consistently with differences in blood pressure during clamped euglycemia, FMD was higher in women than in men (8.06±0.55 vs. 4.15±0.52%, P<0.0001). In contrast, between-group differences in FMD during clamped hyperglycemia did not reach significance owing to a decline in FMD in women, versus men, in response to clamped hyperglycemia (P=0.040 for between-group change in FMD). Clamped hyperglycemia suppresses FMD in women, but not in men, with uncomplicated T1D, which may contribute to the relative loss of protection against renal disease progression in women with T1D.

Cardiovascular risk in type 1 diabetes mellitus

Commonly cardiovascular risk (CVR) is linked to type 2 diabetes mellitus as this type is known to be part of the metabolic syndrome, which includes other cardiovascular factors such as hypertension, dyslipidemia. Inversely, CVR of type 1 diabetes mellitus (T1DM) is currently being debated apart from the occurrence of diabetic nephropathy (DN). For this, we did a review of CVR in patients with T1DM complicated or not with DN. The place of novel non-invasive techniques in screening of subclinical vascular damage is also discussed in this review.

20-HETE and EETs in diabetic nephropathy: a novel mechanistic pathway

Diabetic nephropathy (DN), a major complication of diabetes, is characterized by hypertrophy, extracellular matrix accumulation, fibrosis and proteinuria leading to loss of renal function. Hypertrophy is a major factor inducing proximal tubular epithelial cells injury. However, the mechanisms leading to tubular injury is not well defined. In our study, we show that exposure of rats proximal tubular epithelial cells to high glucose (HG) resulted in increased extracellular matrix accumulation and hypertrophy. HG treatment increased ROS production and was associated with alteration in CYPs 4A and 2C11 expression concomitant with alteration in 20-HETE and EETs formation. HG-induced tubular injury were blocked by HET0016, an inhibitor of CYPs 4A. In contrast, inhibition of EETs promoted the effects of HG on cultured proximal tubular cells. Our results also show that alteration in CYPs 4A and 2C expression and 20HETE and EETs formation regulates the activation of the mTOR/p70S6Kinase pathway, known to play a major role in the development of DN. In conclusion, we show that hyperglycemia in diabetes has a significant effect on the expression of Arachidonic Acid (AA)-metabolizing CYPs, manifested by increased AA metabolism, and might thus alter kidney function through alteration of type and amount of AA metabolites.

Association of CFH and CFB gene polymorphisms with retinopathy in type 2 diabetic patients

Objectives. The complement system is a key component of innate immunity and has been implicated in the pathogenesis of diabetic retinopathy (DR). This study aimed at investigating whether polymorphisms of two genes in the complement pathway, complement factor H (CFH) and complement factor B (CFB), are associated with DR. Methods. 552 well-defined subjects with type 2 diabetes, consisting of 277 DR patients and 275 diabetic controls, were recruited. Four Tag-SNPs rs1048709, rs537160, rs4151657, and rs2072633 in CFB and rs800292 (I62V) in CFH were examined using TaqMan Genotyping Assays. Results. There were significant increases in the frequencies of A allele and AA genotype for rs1048709 in DR patients compared with diabetic controls (P_corr = 0.035, OR = 1.42; P_corr = 0.02, OR = 2.27, resp.): meanwhile, significant decreases in the frequencies of A allele and AA genotype for rs800292 were observed in DR patients compared with diabetic controls (P_corr = 0.04, OR = 0.72; P_corr = 0.015, OR = 0.51, resp.). Joint effect of these two loci was also identified. Moreover, rs800292/AA genotype was found to be related with delayed progression to DR. Conclusions. CFH-rs800292 and CFB-rs1048709 are associated with the presence of DR, which strengthens the concept that complement system plays an important role in the pathogenesis of DR.

Sex-specific-differences in cardiometabolic risk in type 1 diabetes: a cross-sectional study

Background

Little is known about the impact of sex-specific differences in the management of type 1 diabetes (T1DM).

Thus, we evaluated the influence of gender on risk factors, complications, clinical care and adherence in patients with T1DM.

Methods

In a cross-sectional study, sex-specific disparities in glycaemic control, cardiovascular risk factors, diabetic complications, concomitant medication use and adherence to treatment recommendations were evaluated in 225 consecutive patients (45.3% women) who were comparable with respect to age, diabetes duration, and body mass index.

Results

Although women with T1DM had a higher total cholesterol than men, triglycerides were higher in obese men and males with HbA1c>7% than in their female counterparts. No sex differences were observed in glycaemic control and in micro- or macrovascular complications. However, the subgroup analysis showed that nephropathy was more common in obese men, hyperlipidaemic women and all hypertensive patients, whereas peripheral neuropathy was more common in hyperlipidaemic women. Retinopathy was found more frequently in women with HbA1c>7%, obese men and in both sexes with a long duration of diabetes. The multivariate analysis revealed that microvascular complications were associated with the duration of disease and BMI in both sexes and with hyperlipidaemia in males. The overall adherence to interventions according to the guidelines was higher in men than in women. This adherence was concerned particularly with co-medication in patients diagnosed with hypertension, aspirin prescription in elderly patients and the achievement of target lipid levels following the prescription of statins.

Conclusions

Our data showed sex differences in lipids and overweight in patients with T1DM. Although glycaemic control and the frequency of diabetic complications were comparable between the sexes, the overall adherence to guidelines, particularly with respect to the prescription of statins and aspirin, was lower in women than in men.

Sex differences in renal responses to hyperglycemia, L-arginine, and L-NMMA in humans with uncomplicated type 1 diabetes

OBJECTIVE

Women exhibit exaggerated renal hemodynamic responses to hyperglycemia, which may promote kidney disease progression. Our aim was to determine if increased nitric oxide generation by l-arginine infusion would reverse this deleterious response to clamped hyperglycemia in women with type 1 diabetes mellitus.

RESEARCH DESIGN AND METHODS

Renal function, blood pressure, and plasma cyclic guanosine monophosphate (cGMP) were measured in 20 men and 15 women with type 1 diabetes mellitus during clamped euglycemia and clamped hyperglycemia. Renal function, blood pressure, and plasma cGMP responses to graded infusions of intravenous l-arginine and N(G)-monomethyl-l-arginine (l-NMMA) were measured during clamped hyperglycemia.

RESULTS

Subjects were young, normotensive, normoalbuminuric men and women who adhered to a high-sodium, moderate-protein diet. Plasma cGMP levels during euglycemia were generally lower in men compared with women, and systolic blood pressure (SBP) was higher in men. In response to hyperglycemia, cGMP levels did not change in men but did decline in women (Δ-1.10 ± 0.20 vs. Δ+0.05 ± 0.20 pmol/L, between-group effect of hyperglycemia on cGMP; P = 0.012). Hyperglycemia also was associated with an increase in SBP, glomerular filtration rate (GFR) (124 ± 6 to 143 ± 7 mL/min/1.73 m(2); P = 0.003) and filtration fraction (FF) in women, but these parameters did not change in men. In response to l-arginine during hyperglycemia, the increase in cGMP was exaggerated in women versus men and GFR and FF decreased in women only, back toward baseline values observed during clamped euglycemia. l-NMMA infusion did not exaggerate changes in hemodynamic function in response to hyperglycemia.

CONCLUSIONS

 l-Arginine reversed the renal hemodynamic effects of hyperglycemia in women, suggesting that nitric oxide is an important regulator of sex-dependent vascular responses to hyperglycemia in humans.

Assessing progress in retinopathy outcomes in type 1 diabetes: comparing findings from the Wisconsin Diabetes Registry Study and the Wisconsin Epidemiologic Study of Diabetic Retinopathy

OBJECTIVE

The Wisconsin Diabetes Registry Study (WDRS) cohort consisted of patients diagnosed with type 1 diabetes in the same geographic region as, but 8-34 years later than the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) cohort, providing a unique opportunity to assess changes in complications. We estimated the current prevalence and severity of diabetic retinopathy at 20 years of diabetes duration, compared these between eras, and evaluated the influence of diabetes management.

RESEARCH DESIGN AND METHODS

Twenty-year examinations, including fundus photographs, were completed on 305 WDRS subjects during 2007-2011. A subgroup of the WESDR cohort participated in one of four study visits during 1980-1996, at similar diabetes duration (n = 583). Adjusted ordinal logistic regression with three retinopathy severity categories was used to estimate odds ratios (ORs) of more severe retinopathy with diagnosis during an earlier era.

RESULTS

Mean hemoglobin A(1c) (HbA(1c)) was lower in WDRS than in WESDR (8.0% vs. 9.3% [P < 0.001], and 93.4% vs. 21.3% [P < 0.001]) used ≥3 daily insulin injections or an insulin pump. In WDRS, 18% had vision-threatening levels of retinopathy vs. 43% in WESDR. The adjusted OR of more severe retinopathy in the earlier era (OR 3.0 [95% CI 2.2-4.0]) was reduced by including 20-year HbA(1c) in the model (OR 2.2 [1.6-3.0]).

CONCLUSIONS

Retinopathy severity at a diabetes duration of 20 years is lower in the more recent era of type 1 diabetes. Updated projections should be used when informing newly diagnosed individuals of prognosis and for health care cost assessments. Current glycemic control explained a limited amount of the difference.

Prevalence and control of dyslipidaemia among diabetic patients with microalbuminuria in a Chinese hospital

BACKGROUND

Accumulating evidence indicates that dyslipidaemia plays an important role in the progression of kidney disease in patients with diabetes. Hyperlipidaemia is a risk factor for microalbuminuria in patients with diabetes. Little information exists on the prevalence and control of dyslipidaemia among diabetic patients with microalbuminuria in China. The aims of this study were to investigate the prevalence and control of dyslipidaemia among diabetic patients with microalbuminuria in a Chinese hospital as well as factors affecting the disease.

METHODS

A total of 1060 type 2 diabetic inpatients were assigned to the with-microalbuminuria group (n = 635) or the without-microalbuminuria group on the basis of urinary albumin-to-creatinine ratios (UACRs = 30-299 mg/g). Serum levels and the control of lipid profiles were assessed and classified according to the 2011 American Diabetes Association (ADA) guidelines, and low-density lipoprotein-cholesterol (LDL-C) was also assessed and classified according to Chinese intensified control criteria. Multiple regression analyses were performed to examine the factors affecting lipid variables.

RESULTS

Among patients with microalbuminuria, a significantly lower prevalence was found (33.1% vs. 58.6%; 35.3% vs. 52.5%, all p < 0.001) at target levels [LDL-C < 2.60 mmol/L or high-density lipoprotein-cholesterol (HDL-C) > 1.0 mmol/L for men and >1.3 mmol/L for women]. According to the intensified LDL-C goal (<2.07 mmol/L), a lower prevalence was found in male patients (15.5% vs. 32.7%, p < 0.001). Fewer patients with microalbuminuria were adherent to the therapy prescribed for dyslipidaemia (28.8% vs. 43.3%, p < 0.001). Even among patients who were on lipid-lowering treatment, the majority of individuals remained uncontrolled for all three lipid fractions [LDL-C, HDL-C and triglyceride (TG)] (82.5% vs. 69.0%, p = 0.003). Lipid and lipoprotein parameters were associated with gender and age.

CONCLUSION

In China, diabetic patients with microalbuminuria displayed typical dyslipidaemias and were not adequately controlled. Intensified LDL-C and overall lipid-lowering clinical goals are potential precautions taken against diabetic nephropathy.

Differential effect of glycemia on the incidence of hypertension by sex: the epidemiology of diabetes complications study

OBJECTIVE

Diabetes Control and Complications Trial/Epidemiology of Diabetes Intervention and Complications analyses demonstrated that intensive insulin therapy was inversely associated with incident hypertension. We thus sought to confirm these observations and, given sex differences in other type 1 diabetes complications and risk factors, assessed whether any such associations differ by sex.

RESEARCH DESIGN AND METHODS

Participants of a prospective cohort of childhood-onset type 1 diabetes, free of hypertension at study entry (baseline mean age, 28 years; diabetes duration, 19 years), were selected for study (n = 510). Hypertension incidence was defined as blood pressure >140/90 mmHg or use of hypertension medications in two consecutive visits. Intensive insulin therapy was defined as three or more injections (or pump) and four or more glucose tests daily. Baseline predictors of hypertension were examined using Cox proportional hazards models. Models with time-dependent updated means of baseline significant variables were also constructed.

RESULTS

Hypertension incidence over 18 years of follow-up was marginally higher in men than in women (43.2 vs. 35.4%, P = 0.07). A significant interaction was noted between sex and HbA(1c), and separate models were constructed by sex. Multivariably, elevated HbA(1c) was a significant predictor only in men (hazard ratio 1.48 [95% CI 1.28-1.71]). In time-dependent models, although a significant effect of HbA(1c) was also seen in women (1.21 [1.00-1.46]), the effect of glycemic control on hypertension development remained stronger in men (1.59 [1.29-1.97], P interaction <0.0001).

CONCLUSIONS

Although hyperglycemia is a risk factor for hypertension, its effect is stronger in men compared with women with type 1 diabetes.

Predictors of and survival after incident stroke in type 1 diabetes

Few studies have examined stroke risk in type 1 diabetes mellitus (T1DM). Stroke incidence, predictors, and survival were thus explored in this study. Pittsburgh Epidemiology of Diabetes Complications (EDC) Study participants (n = 658) with childhood-onset T1DM were followed biennially for 18 years. Baseline (1986-1988) mean age and diabetes duration were 28 and 19 years respectively. Stroke incidence and type was determined via survey or physician interview and, when possible, confirmed with medical or autopsy records. During follow-up, 31 (4.7%) strokes occurred (21 ischaemic, 8 haemorrhagic, 2 unclassified) in participants of mean age = 40.2 years (range 23-60). In exploratory multivariable Cox modelling, diabetes duration, systolic blood pressure (SBP), non-high density lipoprotein cholesterol (non-HDLc), white blood cells (WBC), and pulse significantly predicted ischaemic stroke. Adding overt nephropathy (ON) (hazard ratio = 4.4, 95% CI, 1.5-12.4) to the model replaced SBP. Participant survival after stroke was 80.6%, 45.2%, and 9.6% at 1, 5, and 10 years, respectively, and significantly worse after haemorrhagic stroke (p = 0.03). These risk factors merit careful evaluation and management to prevent stroke in T1DM, which occurs at least 20 years earlier than in the general population.

Sugar, sex, and TGF-β in diabetic nephropathy

TGF-β is well known to play a critical role in diabetic kidney disease, and ongoing clinical studies are testing the potential therapeutic promise of inhibiting TGF-β production and action. An aspect of TGF-β action that has not received much attention is its potential role in explaining sex-related proclivity for kidney disease. In this review, we discuss recent studies linking TGF-β signaling to sex-related effects in diabetic kidney disease and suggest targets for future studies.

Anti-fibrosis therapy and diabetic nephropathy

Diabetes mellitus is rapidly becoming a global health issue that may overtake cancer during the next two decades as it covertly affects multiple organ systems that goes undiagnosed long after the onset. A number of complications are associated with poorly controlled hyperglycemia. Diabetic nephropathy is one of the most common complications of diabetes mellitus. Other than angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blocker (ARB) there is not much in the armamentarium with which to treat patients with overt diabetic nephropathy. Research points towards a multifactorial etiology and complex interplay of several pathogenic pathways that can contribute to the declining kidney function in diabetes. Patients with diabetic nephropathy (and with any chronic kidney disease) eventually develop kidney fibrosis. Despite the financial and labor investment spent on determining the basic mechanism of fibrosis, not much progress has been made in terms of therapeutic targets available to us today. This may be in part due to paucity in the experimental animal models available. However, there now seems to be a concerted effort from several pharmaceutical companies to develop a drug that would halt/delay the process of fibrosis, if not reverse it. This review discusses the current state of research in the field while staying within the context of diabetic nephropathy.

Kidneys in chronic liver diseases

Acute kidney injury (AKI), defined as an abrupt increase in the serum creatinine level by at least 0.3 mg/dL, occurs in about 20% of patients hospitalized for decompensating liver cirrhosis. Patients with cirrhosis are susceptible to developing AKI because of the progressive vasodilatory state, reduced effective blood volume and stimulation of vasoconstrictor hormones. The most common causes of AKI in cirrhosis are pre-renal azotemia, hepatorenal syndrome and acute tubular necrosis. Differential diagnosis is based on analysis of circumstances of AKI development, natriuresis, urine osmolality, response to withdrawal of diuretics and volume repletion, and rarely on renal biopsy. Chronic glomerulonephritis and obstructive uropathy are rare causes of azotemia in cirrhotic patients. AKI is one of the last events in the natural history of chronic liver disease, therefore, such patients should have an expedited referral for liver transplantation. Hepatorenal syndrome (HRS) is initiated by progressive portal hypertension, and may be prematurely triggered by bacterial infections, nonbacterial systemic inflammatory reactions, excessive diuresis, gastrointestinal hemorrhage, diarrhea or nephrotoxic agents. Each type of renal disease has a specific treatment approach ranging from repletion of the vascular system to renal replacement therapy. The treatment of choice in type 1 hepatorenal syndrome is a combination of vasoconstrictor with albumin infusion, which is effective in about 50% of patients. The second-line treatment of HRS involves a transjugular intrahepatic portosystemic shunt, renal vasoprotection or systems of artificial liver support.

Test characteristics of the ankle-brachial index and ankle-brachial difference for medial arterial calcification on X-ray in type 1 diabetes

OBJECTIVE

Medial arterial calcification (MAC) is common in diabetes, has a characteristic appearance on X-ray imaging, and has been linked with peripheral arterial stiffness and cardiovascular disease. However, few studies have measured X-ray MAC. It has been suggested that an ankle-brachial index (ABI) >1.30 or an ankle-brachial difference (ABD) >75 mm Hg may identify X-ray MAC, but test characteristics are unknown. We hypothesized that an ABI >1.30 and ABD >75 mm Hg would have high specificity but low sensitivity for MAC on X-ray imaging.

METHODS

This was a cross-sectional study of 185 community-living individuals with type 1 diabetes. The ABI and the ABD were assessed. The outcome was linear "tram-track" calcifications in the lower limbs characteristic of MAC.

RESULTS

Mean age was 32 ± 6 years, and mean diabetes duration was 23 ± 7 years. X-ray MAC was noted in 97 individuals (57%), 15 (8%) had ABI >1.30, and 14 (8%) had ABD >75 mm Hg. As assessed by the ABI, the area under the receiver operating characteristic curve for MAC was modest (0.65) and was slightly higher for the ABD (0.75). An ABI >1.30 had high specificity (99%) and positive predictive value (93%) but poor sensitivity (14%) and an overall accuracy of 55% for MAC. An ABD >50 mm Hg remained highly specific (98%) but had higher sensitivity (30%) and overall accuracy (62%).

CONCLUSIONS

Individuals with type 1 diabetes and an ABI >1.30 or ABD >50 mm Hg are very likely to have MAC on X-ray imaging, yet many with MAC will not have an ABI or ABD above these thresholds. Given the high specificity, evaluating high ABI or ABD may be useful to understand correlates of MAC but may underestimate MAC prevalence.

Diabetic neuropathy and axon reflex-mediated neurogenic vasodilatation in type 1 diabetes

Objective

Axon reflex-mediated neurogenic vasodilatation in response to cutaneous heating may reflect early, pre-clinical small fibre dysfunction. We aimed to evaluate the distribution of the vascular flare area measured by laser doppler imaging (“LDI_FLARE area”) in type 1 diabetes and in healthy volunteers.

Research and Methods

Concurrent with clinical and electrophysiological examination to classify diabetic sensorimotor polyneuropathy (DSP), LDI_FLARE area (cm²) was determined in 89 type 1 diabetes subjects matched to 64 healthy volunteers. We examined the association and diagnostic performance of LDI with clinical and subclinical measures of DSP and its severity.

Results

Compared to the 64 healthy volunteers, the 56 diabetes controls without DSP had significantly lower LDI_FLARE area (p = 0.006). The 33 diabetes cases with DSP had substantially lower LDI_FLARE area as compared to controls without DSP (p = 0.002). There was considerable overlap in LDI_FLARE area between all groups such that the ROC curve had an AUC of 0.72 and optimal sensitivity of 70% for the detection of clinical DSP. Use of a subclinical definition for DSP, according to subclinical sural nerve impairment, was associated with improved AUC of 0.75 and sensitivity of 79%. In multivariate analysis higher HbA1c and body mass index had independent associations with smaller LDI_FLARE area.

Conclusions

Axon reflex-mediated neurogenic vasodilatation in response to cutaneous heating is a biomarker of early nerve dysfunction in DSP. Its independent association with glycemic exposure in diabetes subjects and both glycemic exposure and BMI in healthy volunteers highlights the existence of small-fibre dysfunction in the natural history of DSP.

Duration of diabetes and risk of ischemic stroke: the Northern Manhattan Study

BACKGROUND AND PURPOSE

Diabetes increases stroke risk, but whether diabetes status immediately before stroke improves prediction and whether duration is important are less clear. We hypothesized that diabetes duration independently predicts ischemic stroke.

METHODS

Among 3298 stroke-free participants in the Northern Manhattan Study, baseline diabetes and age at diagnosis were determined. Incident diabetes was assessed annually (median, 9 years). Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% CI for incident ischemic stroke using baseline diabetes, diabetes as a time-dependent covariate, and duration of diabetes as a time-varying covariate; models were adjusted for demographic and cardiovascular risk factors.

RESULTS

Mean age was 69 ± 10 years (52% Hispanic, 21% white, and 24% black); 22% had diabetes at baseline and 10% had development of diabetes. There were 244 ischemic strokes, and both baseline diabetes (HR, 2.5; 95% CI, 1.9-3.3) and diabetes considered as a time-dependent covariate (HR, 2.4; 95% CI, 1.8-3.2) were similarly associated with stroke risk. Duration of diabetes was associated with ischemic stroke (adjusted HR, 1.03 per year with diabetes; 95% CI, 1.02-1.04). Compared to nondiabetic participants, those with diabetes for 0 to 5 years (adjusted HR, 1.7; 95% CI, 1.1-2.7), 5 to 10 years (adjusted HR, 1.8; 95% CI, 1.1-3.0), and ≥ 10 years (adjusted HR, 3.2; 95% CI, 2.4-4.5) were at increased risk.

CONCLUSIONS

Duration of diabetes is independently associated with ischemic stroke risk adjusting for risk factors. The risk increases 3% each year, and triples with diabetes ≥ 10 years.

Pulse wave analysis and cardiac autonomic neuropathy in type 1 diabetes: a report from the Pittsburgh Epidemiology of Diabetes Complications Study

BACKGROUND

The cross-sectional associations of cardiac autonomic neuropathy (CAN) with pulse wave analysis (PWA) measures (both arterial stiffness and myocardial perfusion) have not been explored in type 1 diabetes, despite recognition of an association of CAN with coronary artery disease.

METHODS

Both CAN and PWA measures were obtained from 144 participants of the Pittsburgh Epidemiology of Diabetes Complications Study of childhood-onset type 1 diabetes at the 18-year follow-up examination. CAN was measured as variability in the R-R interval during deep breathing, and PWA was performed using SphgymoCor Px (AtCor Medical, Sydney, Australia). Other clinical and demographic factors were also assessed. Univariate and multivariable analyses for associations with CAN were performed for arterial stiffness measures (augmentation index [AIx] and augmentation pressure [AP]) and a myocardial perfusion measure (subendocardial viability ratio [SEVR]).

RESULTS

Presence of CAN was univariately associated with all three PWA measures: AIx (odds ratio [OR]=1.5, P=0.03), AP (OR=2.1, P=0.001), and SEVR (OR=0.4, P<0.001). These relationships persisted after adjustment for potential PWA confounders. Adjusting for age and diabetes-related factors (glycosylated hemoglobin, systolic blood pressure, and overt nephropathy), CAN only remained significantly associated with SEVR (OR=0.3, P=0.005).

CONCLUSIONS

CAN is cross-sectionally associated with measures of both increased arterial stiffness and decreased myocardial perfusion in type 1 diabetes; however, only the association with decreased estimated myocardial perfusion persisted in fully adjusted models. These results provide potential insight into the CAN association with coronary artery disease.

Sex differences in the development of kidney disease in individuals with type 1 diabetes mellitus: a contemporary analysis

BACKGROUND

Kidney disease in patients with type 1 diabetes historically has been believed to be more prevalent in men. Because recent data do not reflect this pattern, we evaluated whether a sex difference persists.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We used 18-year follow-up data from the Pittsburgh Epidemiology of Diabetes Complications Study (n = 788; baseline mean age, 27 years; diabetes duration, 19 years).

PREDICTOR OR FACTOR

Sex and diagnosis interval (1950-1964 or 1965-1980).

OUTCOMES

Cumulative incidences of macroalbuminuria (albumin excretion rate >200 μg/min) and end-stage renal disease (ESRD; kidney failure, dialysis, or transplant) were evaluated at 20, 25, and 30 years of diabetes duration. To address potential survival bias, death certificate information was included in determining ESRD for those who died before baseline (n = 145). Analyses were stratified by diagnosis year (1950-1964 or 1965-1980).

OTHER MEASUREMENTS

Kidney disease risk factor information was available.

RESULTS

A significant interaction was noted between sex and diagnosis cohort for ESRD incidence by 25 (P = 0.002) and 30 (P < 0.001) years' duration. Thus, within the 1950-1964 cohort (210 men and 180 women), ESRD incidence was higher in men compared with women by 25 (30.6% vs 18.0%, respectively) and 30 (43.4% vs 24.6%, respectively) years' duration of type 1 diabetes. However, in the 1965-1980 cohort (260 men and 283 women), the incidence was higher in women (7.6% vs 13.8% by 25 years [P = 0.04] and 13.7% vs 21.0% by 30 years' duration [P = 0.09] in men vs women, respectively). Results were similar for macroalbuminuria.

LIMITATIONS

Study participants were not followed up from the onset of diabetes; thus, risk-factor data from that period are lacking.

CONCLUSIONS

Our data suggest that the male excess of type 1 diabetic kidney disease cases observed in the earlier cohort has been eliminated in the younger cohort. The reason for this dramatic change presently is unclear, but should be addressed in subsequent studies.

High-density lipoprotein cholesterol in diabetes: is higher always better?

BACKGROUND

Recent data suggest that highly elevated high-density lipoprotein cholesterol (HDL-C) may not always protect against cardiovascular disease. To what degree this is true in type 1 diabetes is unknown, although cardiovascular risk is increased despite elevated mean HDL-C.

OBJECTIVE

To reassess the association between HDL-C and its subfractions with coronary artery disease (CAD) in childhood-onset type 1 diabetes.

METHODS

Epidemiology of Diabetes Complications study participants free of CAD at baseline (301 men, 298 women; mean age, 27.1 and diabetes duration, 18.9 years) were studied. CAD was defined as angina, ischemic electrocardiogram changes, confirmed myocardial infarction, angiographic stenosis ≥50%, revascularization, or CAD death. Cholesterol in the HDL fraction and HDL3 cholesterol subfraction was measured enzymatically after precipitation with heparin/manganese and dextran sulfate, respectively.

RESULTS

During 18 years of follow-up, 29.5% of men and 25.5% of women developed CAD. Although a linear decrease in incidence was observed with increasing HDL-C concentration in men, incidence increased in women at less than 47 mg/dL and greater than 80 mg/dL. These patterns largely reflected the HDL3 cholesterol-CAD association. After multivariable adjustment, the linear, inverse, HDL-C/CAD association persisted in men (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.94-0.99); in women, the U-shaped relationship lost significance. HDL3 cholesterol remained multivariably associated with CAD in both men (linear association, P = .03) and women (HR 2.31 (95% CI 1.31-4.08) and HR 1.80 (95% CI 1.01-3.23) for the lowest and highest versus the middle quintiles, respectively).

CONCLUSION

The increased CAD risk in women for an HDL-C >80 mg/dL in type 1 diabetes merits further study. Gender specificity could not be determined as only two men had HDL-C >80 mg/dL.

The assessment of clinical distal symmetric polyneuropathy in type 1 diabetes: a comparison of methodologies from the Pittsburgh Epidemiology of Diabetes Complications Cohort

Distal symmetrical polyneuropathy (DSP) is the most common type of diabetic neuropathy, but often difficult to diagnose reliably. We evaluated the cross-sectional association between three point-of-care devices, Vibratron II, NC-stat(®), and Neurometer(®), and two clinical protocols, MNSI and monofilament, in identifying those with DSP, and/or amputation/ulcer/neuropathic pain (AUP), the two outcomes of major concern. This report presents data from 195 type 1 diabetic participants of the Epidemiology of Diabetes Complications (EDC) Study attending the 18-year examination (2004-2006). Participants with physician-diagnosed DSP, AUP or who were abnormal on the NC-stat, and the Vibratron II, MNSI, and monofilament were older (p<0.05) and had a longer duration of diabetes (p < 0.05). There was no difference by sex for DSP, AUP, or any testing modality, with the exception of NCstat (motor). The Vibratron II and MNSI showed the highest sensitivity for DSP (>87%) and AUP (>80%), whereas the monofilament had the highest specificity (98% DSP, 94% AUP) and positive predictive value (89% DSP, 47% AUP), but lowest sensitivity (20% DSP, 30% AUP). The MNSI also had the highest negative predictive value (83%) and Youden's Index (37%) and currently presents the single best combination of sensitivity and specificity of DSP in type 1 diabetes.

Skin intrinsic fluorescence correlates with autonomic and distal symmetrical polyneuropathy in individuals with type 1 diabetes

OBJECTIVE

To determine whether skin intrinsic fluorescence (SIF) was associated with autonomic neuropathy and confirmed distal symmetrical polyneuropathy (CDSP) in 111 individuals with type 1 diabetes (mean age 49 years, mean diabetes duration 40 years).

RESEARCH DESIGN AND METHODS

SIF was measured using the SCOUT DM device. Autonomic neuropathy was defined as an electrocardiographic abnormal heart rate response to deep breathing (expiration-to-inspiration ratio <1.1). CDSP was defined using the Diabetes Control and Complications Trial clinical exam protocol (the presence of two or more of the following: symptoms, sensory and/or motor signs, and/or reduced/absent tendon reflexes consistent with DSP) confirmed by the presence of an abnormal age-specific vibratory threshold (using a Vibratron II tester).

RESULTS

The prevalence of autonomic neuropathy and CDSP were 61 and 66%, respectively. SIF was higher in those with autonomic neuropathy (P < 0.0001). In multivariable analyses controlling for age and updated mean (18-year average) HbA(1c), and allowing for other univariately and clinically significant correlates of autonomic neuropathy, each SD change in SIF was associated with a 2.6-greater likelihood of autonomic neuropathy (P = 0.006). Receiver operating characteristic (ROC) analyses revealed that SIF and updated mean HbA(1c) accounted for 80 and 57%, respectively, of the area under the curve (AUC) for autonomic neuropathy. SIF also was higher in those with CDSP (P < 0.0001) and remained so in multivariable analyses (odds ratio 2.70; P = 0.005). ROC analyses revealed that SIF and updated mean HbA(1c) accounted for 78 and 59%, respectively, of the AUC for CDSP.

CONCLUSIONS

SIF, a marker of dermal advanced glycation end products, appears to be more strongly associated with the presence of both CDSP and autonomic neuropathy than mean HbA(1c).

Microvascular disease in children and adolescents with type 1 diabetes and obesity

The incidence of type 1 diabetes (T1D) is increasing worldwide and is associated with a significant burden, mainly related to the development of vascular complications. Over the last decades, concomitant with the epidemic of childhood obesity, there has been an increasing number of cases of type 2 diabetes (T2D) among children and adolescents. Microvascular complications of diabetes, which include nephropathy, retinopathy and neuropathy, are characterized by damage to the microvasculature of the kidney, retina and neurons. Although clinically evident microvascular complications are rarely seen among children and adolescents with diabetes, there is clear evidence that their pathogenesis and early signs develop during childhood and accelerate during puberty. Diabetic vascular complications are often asymptomatic during their early stages, and once symptoms develop, there is little to be done to cure them. Therefore, screening needs to be started early during adolescence and, in the case of T2D, already at diagnosis. Identification of risk factors and subclinical signs of complications is essential for the early implementation of preventive and therapeutic strategies, which could change the course of vascular complications and improve the prognosis of children, adolescents and young adults with diabetes.

Carotid intima-media thickness as a surrogate marker of cardiovascular disease in diabetes

BACKGROUND

Diabetes mellitus is associated with a high risk of cardiovascular disease. Carotid intima-media thickness (CIMT) is increasingly used as a surrogate marker for atherosclerosis. Its use relies on its ability to predict future clinical cardiovascular end points.

METHODS

This review examines the evidence linking CIMT as a surrogate marker of vascular complications in people with type 1 and type 2 diabetes. We have also reviewed the various treatment strategies which have been shown to influence CIMT.

CONCLUSIONS

CIMT measurement is an effective, noninvasive tool which can assist in identifying people with diabetes who are at higher risk of developing microvascular and macrovascular complications. It may also help to evaluate the effectiveness of various treatment strategies used to treat people with diabetes.

Midkine, a heparin-binding protein, is increased in the diabetic mouse kidney postmenopause

Estrogen is thought to protect against the development of chronic kidney disease, and menopause increases the development and severity of diabetic kidney disease. In this study, we used streptozotocin (STZ) to induce diabetes in the 4-vinylcyclohexene diepoxide (VCD)-treated mouse model of menopause. DNA microarrays were used to identify gene expression changes in the diabetic kidney postmenopause. An ANOVA model, CARMA, was used to isolate the menopause effect between two groups of diabetic mice, diabetic menopausal (STZ/VCD) and diabetic cycling (STZ). In this diabetic study, 8,864 genes of the possible 15,600 genes on the array were included in the ANOVA; 99 genes were identified as demonstrating a >1.5-fold up- or downregulation between the STZ/VCD and STZ groups. We randomly selected genes for confirmation by real-time PCR; midkine (Mdk), immediate early response gene 3 (IEX-1), mitogen-inducible gene 6 (Mig6), and ubiquitin-specific protease 2 (USP2) were significantly increased in the kidneys of STZ/VCD compared with STZ mice. Western blot analysis confirmed that Mdk and IEX-1 protein abundance was significantly increased in the kidney cortex of STZ/VCD compared with STZ mice. In a separate study, DNA microarrays and CARMA analysis were used to identify the effect of menopause on the nondiabetic kidney; VCD-treated mice were compared with cycling mice. Of the possible 15,600 genes on the array, 9,142 genes were included in the ANOVA; 20 genes were identified as demonstrating a >1.5-fold up- or downregulation; histidine decarboxylase and vanin 1 were among the genes identified as differentially expressed in the postmenopausal nondiabetic kidney. These data expand our understanding of how hormone status correlates with the development of diabetic kidney disease and identify several target genes for further studies.

Variants of the adenosine A(2A) receptor gene are protective against proliferative diabetic retinopathy in patients with type 1 diabetes

AIMS

The adenosine A(2A) receptor (ADORA(2A)) may ameliorate deleterious physiologic effects associated with tissue injury in individuals with diabetes. We explored associations between variants of the ADORA(2A) gene and proliferative diabetic retinopathy (PDR) in a cohort of patients with type 1 diabetes (T1D).

METHODS

The participants were from the Pittsburgh Epidemiology of Diabetes Complications prospective study of childhood-onset T1D. Stereoscopic photographs of the retinal fundus taken at baseline, then biennially, for 10 years were used to define PDR according to the modified Airlie House system. Two tagging single nucleotide polymorphisms (tSNPs; rs2236624-C/T and rs4822489-G/T) in the ADORA(2A) gene were selected using the HapMap (haplotype map) reference database.

RESULTS

A significant association was observed between SNP rs2236624 and PDR in the recessive genetic model. Participants homozygous for the T allele displayed a decreased risk of developing prevalent PDR (odds ratio, OR = 0.36; p = 0.04) and incident PDR (hazard ratio = 0.156; p = 0.009), and for all cases of PDR combined (OR = 0.23; p = 0.001). The protective effect of T allele homozygosity remained after adjusting for covariates. Similarly, for SNP rs4822489, an association between PDR and T allele homozygosity was observed following covariate adjustment (OR = 0.55; 95% CI: 0.31-0.92; p = 0.04).

CONCLUSION

Genetic variants of ADORA(2A) offer statistically significant protection against PDR development in patients with T1D.

In the absence of renal disease, 20 year mortality risk in type 1 diabetes is comparable to that of the general population: a report from the Pittsburgh Epidemiology of Diabetes Complications Study

AIMS/HYPOTHESIS

The FinnDiane Study has reported that mortality in type 1 diabetes is not increased over a 7 year follow-up in the absence of renal disease (RD). Using the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study population (n = 658) of childhood-onset type 1 diabetes (age <17 years), the present study sought to replicate and expand these findings to a 20 year follow-up (as of 1 January 2008) and examine cause of death by renal status.

METHODS

At baseline (1986-1988), mean age and duration of diabetes were 28 and 19 years, respectively. RD was defined as an albumin excretion rate ≥20 μg/min from multiple samples and grouped as microalbuminuria (MA; 20-200 μg/min), overt nephropathy (ON; >200 μg/min), or end stage renal disease (ESRD; dialysis or renal transplantation).

RESULTS

At baseline, 311 (47.3%) individuals had RD (MA 21.3%, ON 22.2% and ESRD 3.8%). During a median 20 year follow-up, there were 152 deaths (23.1%). Mortality was 6.2 (95% CI 5.2-7.2) times higher than expected, with standardised mortality ratios of 2.0 (1.2-2.8) for normoalbuminuria (NA); 6.4 (4.4-8.4) for MA; 12.5 (9.5-15.4) for ON; and 29.8 (16.8-42.9) for ESRD. Excluding those (n = 64) with NA who later progressed to RD, no significant excess mortality was observed in the remaining NA group (1.2, 0.5-1.9), whose deaths were largely unrelated to diabetes.

CONCLUSIONS/INTERPRETATION

These data confirm the importance of RD, including persistent microalbuminuria, as a marker of mortality risk and suggest that type 1 diabetes patients without renal disease achieve long-term survival comparable to the general population.

Betacellulin induces increased retinal vascular permeability in mice

Background

Diabetic maculopathy, the leading cause of vision loss in patients with type 2 diabetes, is characterized by hyper-permeability of retinal blood vessels with subsequent formation of macular edema and hard exudates. The degree of hyperglycemia and duration of diabetes have been suggested to be good predictors of retinal complications. Intervention studies have determined that while intensive treatment of diabetes reduced the development of proliferative diabetic retinopathy it was associated with a two to three-fold increased risk of severe hypoglycemia. Thus we hypothesized the need to identify downstream glycemic targets, which induce retinal vascular permeability that could be targeted therapeutically without the additional risks associated with intensive treatment of the hyperglycemia. Betacellulin is a 32 kD member of the epidermal growth factor family with mitogenic properties for the retinal pigment epithelial cells. This led us to hypothesize a role for betacellulin in the retinal vascular complications associated with diabetes.

Methods and Findings

In this study, using a mouse model of diabetes, we demonstrate that diabetic mice have accentuated retinal vascular permeability with a concomitant increased expression of a cleaved soluble form of betacellulin (s-Btc) in the retina. Intravitreal injection of soluble betacellulin induced retinal vascular permeability in normoglycemic and hyperglycemic mice. Western blot analysis of retinas from patients with diabetic retinopathy showed an increase in the active soluble form of betacellulin. In addition, an increase in the levels of A disintegrin and metalloproteinase (ADAM)-10 which plays a role in the cleavage of betacellulin was seen in the retinas of diabetic mice and humans.

Conclusions

These results suggest that excessive amounts of betacellulin in the retina may contribute to the pathogenesis of diabetic macular edema.

Increase in GLUT1 in smooth muscle alters vascular contractility and increases inflammation in response to vascular injury

OBJECTIVE

The goal of this study was to test the contributing role of increasing glucose uptake in vascular smooth muscle cells (VSMCs) in vascular complications and disease.

METHODS AND RESULTS

A murine genetic model was established in which glucose trasporter 1 (GLUT1), the non-insulin-dependent glucose transporter protein, was overexpressed in smooth muscle using the sm22α promoter. Overexpression of GLUT1 in smooth muscle led to significant increases in glucose uptake (n=3, P<0.0001) as measured using radiolabeled 2-deoxyglucose. Fasting blood glucose, insulin, and nonesterified fatty acids were unchanged. Contractility in aortic ring segments was decreased in sm22α-GLUT1 mice (n=10, P<0.04). In response to vascular injury, sm22α-GLUT1 mice exhibited a proinflammatory phenotype, including a significant increase in the percentage of neutrophils in the lesion (n=4, P<0.04) and an increase in monocyte chemoattractant protein-1 (MCP-1) immunofluorescence. Circulating haptoglobin and glutathione/total glutathione were significantly higher in the sm22α-GLUT1 mice postinjury compared with controls (n=4, P<0.05), suggesting increased flux through the pentose phosphate pathway. sm22α-GLUT1 mice exhibited significant medial hypertrophy following injury that was associated with a significant increase in the percentage of VSMCs in the media staining positive for nuclear phosphoSMAD2/3 (n=4, P<0.003).

CONCLUSIONS

In summary, these findings suggest that increased glucose uptake in VSMCs impairs vascular contractility and accelerates a proinflammatory, neutrophil-rich lesion in response to injury, as well as medial hypertrophy, which is associated with enhanced transforming growth factor-β activity.

Regional adiposity and risk for coronary artery disease in type 1 diabetes: does having greater amounts of gluteal-femoral adiposity lower the risk?

AIMS

Evidence suggests that the degree of gluteal-femoral adiposity may be inversely associated with coronary artery disease (CAD) risk; however, this association has not been evaluated in type 1 diabetes (T1D).

METHODS

The relationship between regional adiposity, cardiovascular risk factors, and presence of CAD was examined in participants from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study using data collected from the 18-year exam (n=163). Total and regional adiposity was assessed by dual X-ray absorptiometry (DEXA).

RESULTS

Participants with CAD exhibited lower % leg fat mass (FM) (33.42 vs. 36.96, p=0.006) and higher % trunk FM (48.33 vs. 45.18, p=0.02), respectively, after adjusting for age, sex, height, and total adiposity compared to those without CAD. Multivariate logistic regression analyses revealed that in females, every 1 SD increase in % leg FM was associated with an approximate 60% reduction in CAD risk (OR=0.40, 95% CI 0.16-0.99). Higher % trunk FM was also associated with greater risk of CAD prevalence in females (OR=2.79, 95% CI 1.08-7.20 per SD change). These associations were not observed in males.

CONCLUSIONS

This is novel evidence that DEXA-assessed lower body adiposity is inversely associated with CAD in T1D, however, this association seems to only exist in females.

Cumulative risk, age at onset, and sex-specific differences for developing end-stage renal disease in young patients with type 1 diabetes: a nationwide population-based cohort study

OBJECTIVE

This study aimed to estimate the current cumulative risk of end-stage renal disease (ESRD) due to diabetic nephropathy in a large, nationwide, population-based prospective type 1 diabetes cohort and specifically study the effects of sex and age at onset.

RESEARCH DESIGN AND METHODS

In Sweden, all incident cases of type 1 diabetes aged 0-14 years and 15-34 years are recorded in validated research registers since 1977 and 1983, respectively. These registers were linked to the Swedish Renal Registry, which, since 1991, collects data on patients who receive active uremia treatment. Patients with > or =13 years duration of type 1 diabetes were included (n = 11,681).

RESULTS

During a median time of follow-up of 20 years, 127 patients had developed ESRD due to diabetic nephropathy. The cumulative incidence at 30 years of type 1 diabetes duration was low, with a male predominance (4.1% [95% CI 3.1-5.3] vs. 2.5% [1.7-3.5]). In both male and female subjects, onset of type 1 diabetes before 10 years of age was associated with the lowest risk of developing ESRD. The highest risk of ESRD was found in male subjects diagnosed at age 20-34 years (hazard ratio 3.0 [95% CI 1.5-5.7]). In female subjects with onset at age 20-34 years, the risk was similar to patients' diagnosed before age 10 years.

CONCLUSIONS

The cumulative incidence of ESRD is exceptionally low in young type 1 diabetic patients in Sweden. There is a striking difference in risk for male compared with female patients. The different patterns of risk by age at onset and sex suggest a role for puberty and sex hormones.

Role of triglyceride-rich lipoproteins in diabetic nephropathy

Diabetic nephropathy is an increasingly important cause of morbidity and mortality worldwide. A large body of evidence suggests that dyslipidemia has an important role in the progression of kidney disease in patients with diabetes. Lipids may induce renal injury by stimulating TGF-beta, thereby inducing the production of reactive oxygen species and causing damage to the glomeruli and glomerular glycocalyx. Findings from basic and clinical studies strongly suggest that excess amounts of a variety of lipoproteins and lipids worsens diabetes-associated microvascular and macrovascular disease, increases glomerular injury, increases tubulointerstitial fibrosis, and accelerates the progression of diabetic nephropathy. The increasing prevalence of obesity, type 2 diabetes mellitus, and diabetic nephropathy means that interventions that can interrupt the pathophysiological cascade of events induced by lipoproteins and lipids could enable major life and cost savings. This Review discusses the structural, cellular, and microscopic findings associated with diabetic nephropathy and the influence of lipoproteins, specifically triglyceride-rich lipoproteins (TGRLs), on the development and perpetuation of diabetic nephropathy. Some of the accepted and hypothesized mechanisms of renal injury relating to TGRLs are also described.