Epidemiology of late diabetic complications. A basis for the development and evaluation of preventive programs

Improved postprandial glucose metabolism in type 2 diabetes by the dual glucagon-like peptide-1/glucagon receptor agonist SAR425899 in comparison with liraglutide

AIM

To gain further insights into the efficacy of SAR425899, a dual glucagon-like peptide-1/glucagon receptor agonist, by providing direct comparison with the glucagon-like peptide-1 receptor agonist, liraglutide, in terms of key outcomes of glucose metabolism.

RESEARCH DESIGN AND METHODS

Seventy overweight to obese subjects with type 2 diabetes (T2D) were randomized to receive once-daily subcutaneous administrations of SAR425899 (0.12, 0.16 or 0.20 mg), liraglutide (1.80 mg) or placebo for 26 weeks. Mixed meal tolerance tests were conducted at baseline (BSL) and at the end of treatment (EOT). Metabolic indices of insulin action and secretion were assessed via Homeostasis Model Assessment (HOMA2) and oral minimal model (OMM) methods.

RESULTS

From BSL to EOT (median [25th, 75th] percentile), HOMA2 quantified a significant improvement in basal insulin action in liraglutide (35% [21%, 74%]), while secretion enhanced both in SAR425899 (125% [63%, 228%]) and liraglutide (73% [43%, 147%]). OMM quantified, both in SAR425899 and liraglutide, a significant improvement in insulin sensitivity (203% [58%, 440%] and 36% [21%, 197%]), basal beta-cell responsiveness (67% [34%, 112%] and 40% [16%, 59%]), and above-basal beta-cell responsiveness (139% [64%, 261%] and 69% [-15%, 120%]). A significant delay in glucose absorption was highlighted in SAR425899 (37% [52%,18%]).

CONCLUSIONS

SAR425899 and liraglutide improved postprandial glucose control in overweight to obese subjects with T2D. A significantly higher enhancement in beta-cell function was shown by SAR425899 than liraglutide.

Type 2 Diabetes Mellitus and Cardiovascular Disease: Genetic and Epigenetic Links

Type 2 diabetes mellitus (DM) is a common metabolic disorder predisposing to diabetic cardiomyopathy and atherosclerotic cardiovascular disease (CVD), which could lead to heart failure through a variety of mechanisms, including myocardial infarction and chronic pressure overload. Pathogenetic mechanisms, mainly linked to hyperglycemia and chronic sustained hyperinsulinemia, include changes in metabolic profiles, intracellular signaling pathways, energy production, redox status, increased susceptibility to ischemia, and extracellular matrix remodeling. The close relationship between type 2 DM and CVD has led to the common soil hypothesis, postulating that both conditions share common genetic and environmental factors influencing this association. However, although the common risk factors of both CVD and type 2 DM, such as obesity, insulin resistance, dyslipidemia, inflammation, and thrombophilia, can be identified in the majority of affected patients, less is known about how these factors influence both conditions, so that efforts are still needed for a more comprehensive understanding of this relationship. The genetic, epigenetic, and environmental backgrounds of both type 2 DM and CVD have been more recently studied and updated. However, the underlying pathogenetic mechanisms have seldom been investigated within the broader shared background, but rather studied in the specific context of type 2 DM or CVD, separately. As the precise pathophysiological links between type 2 DM and CVD are not entirely understood and many aspects still require elucidation, an integrated description of the genetic, epigenetic, and environmental influences involved in the concomitant development of both diseases is of paramount importance to shed new light on the interlinks between type 2 DM and CVD. This review addresses the current knowledge of overlapping genetic and epigenetic aspects in type 2 DM and CVD, including microRNAs and long non-coding RNAs, whose abnormal regulation has been implicated in both disease conditions, either etiologically or as cause for their progression. Understanding the links between these disorders may help to drive future research toward an integrated pathophysiological approach and to provide future directions in the field.

Identification of type 2 diabetes subgroups through topological analysis of patient similarity

Type 2 diabetes (T2D) is a heterogeneous complex disease affecting more than 29 million Americans alone with a rising prevalence trending toward steady increases in the coming decades. Thus, there is a pressing clinical need to improve early prevention and clinical management of T2D and its complications. Clinicians have understood that patients who carry the T2D diagnosis have a variety of phenotypes and susceptibilities to diabetes-related complications. We used a precision medicine approach to characterize the complexity of T2D patient populations based on high-dimensional electronic medical records (EMRs) and genotype data from 11,210 individuals. We successfully identified three distinct subgroups of T2D from topology-based patient-patient networks. Subtype 1 was characterized by T2D complications diabetic nephropathy and diabetic retinopathy; subtype 2 was enriched for cancer malignancy and cardiovascular diseases; and subtype 3 was associated most strongly with cardiovascular diseases, neurological diseases, allergies, and HIV infections. We performed a genetic association analysis of the emergent T2D subtypes to identify subtype-specific genetic markers and identified 1279, 1227, and 1338 single-nucleotide polymorphisms (SNPs) that mapped to 425, 322, and 437 unique genes specific to subtypes 1, 2, and 3, respectively. By assessing the human disease-SNP association for each subtype, the enriched phenotypes and biological functions at the gene level for each subtype matched with the disease comorbidities and clinical differences that we identified through EMRs. Our approach demonstrates the utility of applying the precision medicine paradigm in T2D and the promise of extending the approach to the study of other complex, multifactorial diseases.

Early Predictors for Lower Extremity Amputation in a Diabetic Population: Results of a Case-Controlled Study

Lower extremity amputation is devastating to any person and is a very real complication for a diabetic. Identifying early risk factors is tantamount to saving a limb. This study used the national hospital discharge survey to identify 2206 control patients and 2098 diabetic patients with a lower extremity amputation. These patients were not limited based on gender or race as in previous studies. The results show that nephropathy and retinopathy are early predictors.

Association of Single Nucleotide Polymorphisms of Adiponectin Gene with Type 2 Diabetes Mellitus, and Their Influence on Cardiovascular Risk Markers

Type 2 diabetes mellitus is a genetically heterogeneous condition, characterized by insulin deficiency and/or insulin resistance. The etiology of type 2 diabetes is complex, with involvement of genetic and environmental factors. The adipose tissue protein 'adiponectin' is known to increase insulin sensitivity with decreased risk of type 2 diabetes mellitus. The gene for adiponectin is present on chromosome 3q27, the association of number of single nucleotide polymorphisms of adiponectin gene with type 2 diabetes and its complications have been reported. In the present study the two most common SNPs +45T/G & +276G/T, and their association with type 2 diabetes mellitus and cardiovascular markers were studied. The significant difference in genotype frequencies of +45T/G & +276G/T was found in type 2 diabetic patients and controls, with odds ratio of 1.13 & 1.26 respectively. BMI, Fasting blood glucose, fasting insulin, HOMA IR, triglyceride and VLDL cholesterol levels were increased, and HDL cholesterol level was decreased in patients carrier for +45T/G SNP than the wild type. While only decrease in the HDL cholesterol was reported in carriers for SNP +276G/T than the wild type. The logistic regression analysis revealed the positive association of SNP +45T/G with total cholesterol & LDL cholesterol. And negative association of HDL cholesterol was found with SNPs +45T/G and +276G/T. The haplotype analysis shows the alterations in means of biochemical markers in the patients having haplotype (GG) for mutant allele of SNP +45T/G and wild allele for SNP +276G/T.

Resistance Exercise in Already-Active Diabetic Individuals (READI): study rationale, design and methods for a randomized controlled trial of resistance and aerobic exercise in type 1 diabetes

The Resistance Exercise in Already Active Diabetic Individuals (READI) trial aimed to examine whether adding a 6-month resistance training program would improve glycemic control (as reflected in reduced HbA₁c) in individuals with type 1 diabetes who were already engaged in aerobic exercise compared to aerobic training alone. After a 5-week run-in period including optimization of diabetes care and low-intensity exercise, 131 physically active adults with type 1 diabetes were randomized to two groups for 22weeks: resistance training three times weekly, or waiting-list control. Both groups maintained the same volume, duration and intensity of aerobic exercise throughout the study as they did at baseline. HbA₁c, body composition, frequency of hypoglycemia, lipids, blood pressure, apolipoproteins B and A-1 (ApoB and ApoA1), the ApoB-ApoA1 ratio, urinary albumin excretion, serum C-reactive protein, free fatty acids, total daily insulin dose, health-related quality of life, cardiorespiratory fitness and musculoskeletal fitness were recorded at baseline, 3 (for some variables), and 6 months. To our knowledge, READI is the only trial to date assessing the incremental health-related impact of adding resistance training for individuals with type 1 diabetes who are already aerobically active. Few exercise trials have been completed in this population, and even fewer have assessed resistance exercise. With recent improvements in the quality of diabetes care, the READI study will provide conclusive evidence to support or refute a major clinically relevant effect of exercise type in the recommendations for physical activity in patients with type 1 diabetes.

Recent advances in the molecular genetics of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a complex disease in which both genetic and environmental factors interact in determining impaired β-cell insulin secretion and peripheral insulin resistance. Insulin resistance in muscle, liver and fat is a prominent feature of most patients with T2DM and obesity, resulting in a reduced response of these tissues to insulin. Considerable evidence has been accumulated to indicate that heredity is a major determinant of insulin resistance and T2DM. It is believed that, among individuals destined to develop T2DM, hyperinsulinemia is the mechanism by which the pancreatic β-cell initially compensates for deteriorating peripheral insulin sensitivity, thus ensuring normal glucose tolerance. Most of these people will develop T2DM when β-cells fail to compensate. Despite the progress achieved in this field in recent years, the genetic causes of insulin resistance and T2DM remain elusive. Candidate gene association, linkage and genome-wide association studies have highlighted the role of genetic factors in the development of T2DM. Using these strategies, a large number of variants have been identified in many of these genes, most of which may influence both hepatic and peripheral insulin resistance, adipogenesis and β-cell mass and function. Recently, a new gene has been identified by our research group, the HMGA1 gene, whose loss of function can greatly raise the risk of developing T2DM in humans and mice. Functional genetic variants of the HMGA1 gene have been associated with insulin resistance syndromes among white Europeans, Chinese individuals and Americans of Hispanic ancestry. These findings may represent new ways to improve or even prevent T2DM.

Role of podocyte B7-1 in diabetic nephropathy

Podocyte injury and resulting albuminuria are hallmarks of diabetic nephropathy, but targeted therapies to halt or prevent these complications are currently not available. Here, we show that the immune-related molecule B7-1/CD80 is a critical mediator of podocyte injury in type 2 diabetic nephropathy. We report the induction of podocyte B7-1 in kidney biopsy specimens from patients with type 2 diabetes. Genetic and epidemiologic studies revealed the association of two single nucleotide polymorphisms at the B7-1 gene with diabetic nephropathy. Furthermore, increased levels of the soluble isoform of the B7-1 ligand CD28 correlated with the progression to ESRD in individuals with type 2 diabetes. In vitro, high glucose conditions prompted the phosphatidylinositol 3 kinase-dependent upregulation of B7-1 in podocytes, and the ectopic expression of B7-1 in podocytes increased apoptosis and induced disruption of the cytoskeleton that were reversed by the B7-1 inhibitor CTLA4-Ig. Podocyte expression of B7-1 was also induced in vivo in two murine models of diabetic nephropathy, and treatment with CTLA4-Ig prevented increased urinary albumin excretion and improved kidney pathology in these animals. Taken together, these results identify B7-1 inhibition as a potential therapeutic strategy for the prevention or treatment of diabetic nephropathy.

Renal function is ameliorated in a diabetic nephropathy rat model through a duodenal-jejunal bypass

AIMS

Diabetes surgery is growing in popularity and has been shown to have marked effects on diabetes. However, several studies have shown it may induce some renal injury, and, currently, the impact of diabetes surgery on renal function is unclear. In this study, we examined renal function and histological changes in rats with diabetic nephropathy (DN) following a duodeno-jejunal bypass (DJB) operation.

METHODS

Rats with streptozotocin (STZ)-induced diabetes were randomly assigned to 3 groups: DJB group (DJB), Sham-DJB group (S-DJB) and diabetes group (DM). Six age-matched normal rats were assigned as the control group. DJB and sham surgery were performed. Body weight, food intake, glucose levels, lipid parameters, cystatin C (Cys_C) levels, serum and urinary creatinine, 24h urine albumin excretion rate (UAER) and glomerular filtration rate (GFR) were measured. Histological analysis and immunohistochemical studies of renal sections were also performed.

RESULTS

DJB ameliorated renal function by improving UAER, GFR and Cys_C levels 4 and 8 weeks after surgery. It also improved lipid metabolism by decreasing fasting total serum cholesterol (TC) and triglyceride (TG) levels. Immuno-staining of synaptopodin showed podocyte injury was also improved in DJB glomeruli compared with sham and DM groups. Histological analysis showed that the mesangial expansion was not significantly prevented 8 weeks after DJB surgery.

CONCLUSION

DJB ameliorated renal function in UAER and GFR but not mesangial expansion in a DN rat model. The improvement of renal function may be attributed to reversing the injury or loss of podocytes after DJB surgery.

Hyperglycemia is independently associated with post-operative function loss in patients with primary eloquent glioblastoma

The poor prognosis for patients with glioblastoma (GB) heightens the importance of maintaining function throughout treatment. Hyperglycemia has been linked to poor neurological outcomes following stroke, traumatic brain and spinal cord injury. We hypothesized this may also be true following the resection of GB. We assessed associations with post-operative function with the goal of identifying modifiable factors in the peri-operative period with a particular focus on blood glucose levels. Independent associations with worse post-operative function included: patient age, pre-operative motor deficit, deep tumor location, post-operative motor deficit, and elevated mean peri-operative glucose. Interestingly, controlling for associated factors including dexamethasone dosing, patients with elevated peri-operative glucose levels were nearly twice as likely to have new post-operative neurological deficits. These results suggest, together with the broad literature supporting a role for hyperglycemia in neurological injury, that this may represent a modifiable factor in the peri-operative care of these patients.

Evaluation of resistive index by color Doppler imaging of orbital arteries in type II diabetes mellitus patients with microalbuminuria

OBJECTIVE

Resistive index (RI) is an indirect measurement of blood flow resistance that can be used to evaluate vascular damage in ophthalmologic diseases. The purpose of this study was to evaluate the association between RI values of orbital arteries by using the color Doppler imaging (CDI) in type II diabetes mellitus (DM) patients with microalbuminuria.

PATIENTS AND METHODS

We evaluated 91 type II DM patients with microalbuminuria and 27 healthy subjects. The DM patients with microalbuminuria were grouped into two: group 1 consisted of patients with retinopathy (n = 51) and group 2 consisted of patients without retinopathy (n = 40). Healthy subjects constituted group 3 (n = 27). The mean RI values of ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured using CDI.

RESULTS

Compared to diabetic group 2, group 1 had significantly higher mean RIs of OA, CRA, PCA, and HbA1c levels (p < 0.001 for all). Besides, there were no statistical differences in mean RIs of OA, CRA, and PCA between the control group and group 2 (p = 1.0; p = 0.44; p = 0.67, respectively). Mean RIs of OA and PCA were significantly correlated with age in group 1 (r = 0.549, p < 0.001; r = 0.407, p = 0.003, respectively). Mean RI of CRA was significantly correlated with the duration of diabetes and age in group 1 (r = 0.296, p = 0.035; r = 0.486, p < 0.001, respectively).

CONCLUSION

Our study indicates that RI might be a useful marker for early diagnosis and follow-up of diabetic retinopathy, and orbital RI assessment would be beneficial for diabetic patients with retinopathy.

Personalized Medicine in Diabetes

BACKGROUND

Multiple genes that are associated with the risk of developing diabetes or the risk of diabetes complications have been identified by candidate gene analysis and genomewide scanning. These molecular markers, together with clinical data and findings from proteomics, metabolomics, pharmacogenetics, and other methods, lead to a consideration of the extent to which personalized approaches can be applied to the treatment of diabetes mellitus.

CONTENT

Known genes that cause monogenic subtypes of diabetes are reviewed, and several examples are discussed in which the genotype of an individual with diabetes can direct considerations of preferred choices for glycemic therapy. The extent of characterization of polygenic determinants of type 1 and type 2 diabetes is summarized, and the potential for using this information in personalized management of glycemia and complications in diabetes is discussed. The application and current limitations of proteomic and metabolomic methods in elucidating diabetes heterogeneity is reviewed.

SUMMARY

There is established heterogeneity in the determinants of diabetes and the risk of diabetes complications. Understanding the basis of this heterogeneity provides an opportunity for personalizing prevention and treatment strategies according to individual patient clinical and molecular characteristics. There is evidence-based support for benefits from a personalized approach to diabetes care in patients with certain monogenic forms of diabetes. It is anticipated that strategies for individualized treatment decisions in the more common forms of diabetes will emerge with expanding knowledge of polygenic factors and other molecular determinants of disease.

The natural course of microalbuminuria among African Americans with type 2 diabetes: a 3-year study

BACKGROUND

The natural course of microalbuminuria in African Americans (AA) with type 2 diabetes is not well established.

METHOD

Longitudinal analysis of 186 African Americans with type 2 diabetes enrolled in Project Sugar, a randomized controlled trial of primary care-based interventions to improve diabetes control.

RESULTS

Mean age was 59.4 years and 85% were female. Mean estimated glomerular filtration rate and urinary albumin-to-creatinine ratio were 75.90 mL/min/1.73 m(2) and 1.62, respectively. Thirty-nine patients had macroalbuminuria and significantly higher systolic blood pressure compared with those with microalbuminuria (P=.01). Sixty patients had microalbuminuria, 19 progressed to macroalbuminuria, and none regressed. Progression was associated significantly with systolic blood pressure >or=115 mm Hg and requirement for blood pressure medication in the univariate model. In the multivariate model, the degree of albumin-to-creatinine ratio (odds ratio 35.51, 95% confidence interval, 2.21-571.65) and need for blood pressure medication (odds ratio 8.96, 95% confidence interval, 1.35-59.70) were independently associated with progression. No association was observed with the use of specific antihypertensive agent.

CONCLUSION

This study suggests that African Americans with type 2 diabetes and microalbuminuria experience irreversible disease that not infrequently progresses to overt proteinuria. The degree of microalbuminuria and blood pressure are key determinants in this process and should be primary targets in treating this population regardless of the antihypertensive class used.

Reproductive history and hormonal birth control use are associated with coronary calcium progression in women with type 1 diabetes mellitus

CONTEXT

Coronary artery disease is increased in women with type 1 diabetes (T1D), compared with nondiabetic (Non-DM) women. Women with T1D have more menstrual dysfunction and are less likely to use hormonal birth control (BC) than Non-DM women.

OBJECTIVE

The purpose of this study was to determine whether coronary artery calcium (CAC) is associated with menstrual dysfunction and BC use in women with T1D.

MATERIALS AND METHODS

This was a prospective cohort study, and participants were followed up for an average of 2.4 yr.

PATIENTS

Patients included 612 women (293 T1D, 319 Non-DM) between the ages of 19 and 55 yr who had CAC measured twice by electron beam tomography.

RESULTS

Irregular menses and amenorrhea were more common in T1D than Non-DM women (22.1 vs. 14.9%, P < 0.05 and 16.6 vs. 7.0%, P < 0.001). T1D women reported less BC use than Non-DM women (79.8 vs. 89.9%, P < 0.001) and reached menarche at an older age (13.1 +/- 1.8 vs. 12.8 +/- 1.5 yr, P < 0.05). Use of BC was associated with less CAC progression in all women, but this association was stronger in T1D women (P value for interaction = 0.02). Irregular menses were associated with greater CAC progression only among T1D women.

CONCLUSIONS

A prior history of BC use is associated with reduced CAC progression among all women, with a stronger association in T1D than in Non-DM women. Women with T1D who report irregular menses have increased CAC progression, compared with those with regular menses.

Colour Doppler ultrasound evaluation of orbital vessels in diabetic retinopathy

The aim of this study was to determine the role of colour Doppler imaging in the retrobulbar vascular circulation in diabetic retinopathy (DR). Maximum (V(max)), end-diastolic (V(min)) and average (V(mean)) velocities of blood flows and pulsatility index and resistivity index (RI) in central retinal artery (CRA), short branches of posterior ciliary artery (PCA) and ophthalmic artery of the 65 diabetic and 22 control eyes were measured. The CRA V(max) level in the control group was significantly higher than in DR groups. The CRA V(mean) level was also significantly higher in the control group than in the mild nonproliferative diabetic retinopathy (NPDR) and the moderate NPDR groups. The CRA RI value was significantly higher in the control group than in the nonretinopathy group. The CRA V(min) and the ophthalmic artery RI values were found significantly higher in the nonretinopathy group than in the moderate NPDR group. There were significant decreases in the some CRA and PCA values as glycated haemoglobin (HbA1c) levels increase in diabetic group. There was a positive correlation between the duration of diabetes and HbA1c levels. This study showed the presence of some dynamic circulatory alterations in the nonretinopathy group with diabetes and DR groups. It was also shown that there is a negative correlation between HbA1c and some orbital vascular velocities.

Rationale and implementation of the SLICK project: Screening for Limb, I-Eye, Cardiovascular and Kidney (SLICK) complications in individuals with type 2 diabetes in Alberta's First Nations communities

OBJECTIVE

Identifying diabetes complications through screening using portable laboratory equipment in Aboriginal communities, and providing education and client empowerment for improved follow-up care and self-care.

PARTICIPANTS

First Nations people with known diabetes.

SETTING

Screening was carried out in temporary clinics and laboratories set up at the local health centre in each of Alberta's 44 First Nations.

INTERVENTION

Two mobile units ("SLICK vans"), equipped with professionally trained staff, portable lab instruments and a retinal camera, travelled to all 44 Alberta First Nations communities to facilitate implementation of the Canadian Diabetes Association Clinical Practice Guidelines (CPGs). The project provided relevant education and counselling in conjunction with screening activities.

OUTCOMES

SLICK screened 1,151 clients between December 2001 and July 2003, and the project remains ongoing. A preliminary evaluation of the project's 19-month implementation period showed screening activities and satisfaction with diabetes services were low prior to SLICK. There were modest improvements in some program outcomes at 6-12 months follow-up.

CONCLUSION

The SLICK project is designed to address the impact of diabetes by utilizing evidence-based CPGs with respect to screening for complications at the community level. It had a successful implementation period facilitated by community acceptance.

Who is tested for diabetic kidney disease and who initiates treatment? The Translating Research Into Action For Diabetes (TRIAD) Study

OBJECTIVE

We examined factors associated with screening for albuminuria and initiation of ACE inhibitor or angiotensin receptor blocker (ARB) treatment in diabetic patients.

RESEARCH DESIGN AND METHODS

We conducted surveys and medical record reviews for 5,378 patients participating in a study of diabetes care in managed care at baseline (2000-2001) and follow-up (2002-2003). Factors associated with testing for albuminuria were examined in cross-sectional analysis at baseline. Factors associated with initiating ACE inhibitor/ARB therapy were determined prospectively.

RESULTS

At baseline, 52% of patients not receiving ACE inhibitor/ARB therapy and without known diabetic kidney disease (DKD) were screened for albuminuria. Patients > or =65 years of age, those with higher HbA(1c), those with cardiovascular disease (CVD), and those without hyperlipidemia were less likely to be screened. Of the patients with positive screening tests, 47% began ACE inhibitor/ARB therapy. Initiation of therapy was associated with positive screening test results, BMI > or =25 kg/m(2), treatment with insulin or oral antidiabetic agents, peripheral neuropathy, systolic blood pressure > or =140 mmHg, and CVD. Of the patients receiving ACE inhibitor/ARB therapy or with known DKD, 63% were tested for albuminuria.

CONCLUSIONS

Screening for albuminuria was inadequate, especially in older patients or those with competing medical concerns. The value of screening could be increased if more patients with positive screening tests initiated ACE inhibitor/ARB therapy. The efficiency of screening could be improved by limiting screening to diabetic patients not receiving ACE inhibitor/ARB therapy and without known DKD.

Codelivery of a tea extract prevents morbidity and mortality associated with oral vanadate therapy in streptozotocin-induced diabetic rats

Oral administration of vanadate has a strong hypoglycemic effect but results in toxic side effects like life-threatening diarrhea. Tea is known to have potent antidiarrhea effects. We investigated the potential of suspending the vanadate in a tea decoction to reduce the diarrheatic action of vanadate. A concentrated extract of Lichee black tea was, therefore, added to sodium orthovanadate. Streptozotocin (STZ)-induced diabetic rats were orally gavaged with vanadate suspended in water or in the tea decoction, or with the tea extract alone. Blood glucose levels were assessed daily over 11 weeks with levels greater than 10 mmol/L warranting therapeutic intervention. Both the vanadate/water and vanadate/tea solutions acutely reduced blood glucose. The tea extract alone had no effect. The majority of vanadate/water-treated rats developed diarrhea and mortality rates approached 40%. Vanadate/tea-treated diabetic rats experienced no diarrhea or mortality and liver and kidney analyses (plasma ALT and creatinine, blood urea nitrogen [BUN], and urine-specific gravity) were normal. Animals treated with vanadate/tea retained blood glucose levels less than 10 mmol/L for an average of 24 consecutive days without subsequent treatments. Cataract formation was completely prevented. The mechanism of action of vanadate may have involved beta-cell stimulation because vanadate/tea-treated diabetic rats exhibited normal plasma insulin levels. In summary, because of its long-lasting effects, oral administration, and lack of side effects, vanadate/tea represents a potentially important alternative therapy for an insulin-deficient diabetic state.

Poor glycemic control is associated with increased diastolic blood pressure and heart rate in children with Type 1 diabetes

Although higher levels of hemoglobin A1c (HbA1c) and blood pressure precede the development of nephropathy in Type 1 diabetes (T1DM), the relationship between glycemic control and cardiovascular factors early in the course of diabetes is not clear. We conducted a retrospective study from clinic data for a 1-year period in 148 children with T1DM aged 12.5+/-4.4 years who had average diabetes duration of 4.5+/-3.3 years. The influence of HbA1c and reported insulin dose on blood pressure and heart rate were analyzed in multivariate linear regression models, statistically adjusted for the effect of race, sex, age, body mass index, and duration of diabetes. There was a significant positive correlation of mean HbA1c with mean diastolic blood pressure (P<.025) and mean heart rate (P<.0004). Higher diastolic blood pressure and heart rate were associated with higher HbA1c. Increased insulin doses were also associated with increased diastolic blood pressure (P<.009) and heart rate (P<.013). Insulin dose and HbA1c were also significantly correlated (P<.001). There was no correlation between mean HbA1c and mean systolic blood pressure. Increased levels of HbA1c and insulin dose are associated with increased diastolic blood pressure and heart rate. Although within the normal range, early increases of diastolic blood pressure and heart may indicate early cardiovascular changes in response to diabetes and potentially contribute to a greater proclivity for later development of nephropathy.

Diabetes mellitus and optic atrophy: a study of Wolfram syndrome in the Lebanese population

Wolfram syndrome (WFS) is a rare hereditary neurodegenerative disorder also known as DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). WFS seems to be a heterogeneous disease that has not yet been fully characterized in terms of clinical features and pathophysiological mechanisms because the number of patients in most series was small. In this study we describe 31 Lebanese WFS patients belonging to 17 families; this, to our knowledge, is the largest number of patients reported in one series so far. Criteria for diagnosis of WFS were the presence of insulin-dependent diabetes mellitus and optic atrophy unexplained by any other disease. Central diabetes insipidus was found in 87% of the patients, and sensorineural deafness confirmed by audiograms was present in 64.5%. Other less frequent features included neurological and psychiatric abnormalities, urodynamic abnormalities, limited joint motility, cardiovascular and gastrointestinal autonomic neuropathy, hypergonadotropic hypogonadism in males, and diabetic microvascular disease. New features, not reported in previous descriptions, such as heart malformations and anterior pituitary dysfunction, were recognized in some of the patients and participated in the morbidity and mortality of the disease. Genetic analysis revealed WFS1 gene mutations in three families (23.5%), whereas no abnormalities were detected in mitochondrial DNA. In conclusion, WFS is a devastating disease for the patients and their families. More information about WFS will lead to a better understanding of this disease and hopefully to improvement in means of its prevention and treatment.

Impact of simultaneous pancreas and kidney transplantation on progression of coronary atherosclerosis in patients with end-stage renal failure due to type 1 diabetes

OBJECTIVE

Mortality in type 1 diabetic patients with end-stage renal failure is high and dominated by coronary atherosclerotic events. With regard to prognosis, simultaneous transplantation of pancreas and kidney (SPK) may be superior to kidney transplantation alone (KTA) in type 1 diabetic patients, because normalization of blood glucose levels may reduce progression of coronary atherosclerosis and because it is well known that progression of coronary atherosclerosis is one of the major factors that determines clinical prognosis. However, no data are available on progression of coronary atherosclerosis after SPK.

RESEARCH DESIGN AND METHODS

We performed an observational angiographic study comparing progression of coronary atherosclerosis, analyzed with quantitative coronary angiography, in patients with (n = 26) and those without (n = 6) a functioning pancreas graft after SPK, to test the hypothesis that normalization of blood glucose levels by SPK may indeed reduce progression of coronary atherosclerosis in type 1 diabetic patients and thereby improve prognosis.

RESULTS

Mean follow-up was 3.9 years. Average glucose control was significantly worse for the patients without a pancreas graft than for patients with a functioning pancreas graft: 11.3 (SD 3.5) vs. 5.9 mmol/l (SD 1.1) (P = 0.03). Mean segment diameter loss (progression of diffuse coronary atherosclerosis) was 0.024 mm/year (SD 0.067) in patients with a functioning pancreas graft, compared with 0.044 mm/year (SD 0.038) in patients in whom the pancreas graft was lost. Minimum obstruction diameter loss (progression of focal coronary atherosclerosis) was 0.037 mm/year (SD 0.086) in patients with a functioning pancreas graft compared with 0.061 mm/year (SD 0.038) in patients in whom the pancreas graft was lost. Regression of atherosclerosis occurred in 38% of patients with a functioning pancreas graft compared with 0% of patients of whom the pancreas graft was lost (P = 0.035).

CONCLUSIONS

Our study provides, for the first time, evidence that in patients who have undergone SPK, progression of coronary atherosclerosis in patients with a functioning pancreas graft is reduced compared with patients with pancreas graft failure. Our observation is an important part of the explanation for the observed improved mortality rates reported in type 1 diabetic patients with end-stage renal failure after SPK compared with KTA. In light of these findings described above, SPK must to be carefully considered for all diabetic transplant candidates.

Existe concordância no acometimento renal e retiniano da microangiopatia diabética?

Avaliamos associações da microangiopatia a fatores de risco, a correlação entre nefropatia (ND) e retinopatia (RD) diabéticas, assim como a concordância entre os graus de acometimento destes territórios. 157 pacientes, submetidos a oftalmoscopia indireta, foram encaminhados ao Centro de Diabetes para pesquisa de ND, sendo obtidos dados sócio-demográficos e clínicos. Avaliou-se o controle glicêmico pela hemoglobina glicosilada e a presença de ND pela microalbuminúria. Atribuiu-se escores à RD e ND para análises de correlação e concordância. 103 pacientes (57,9±12,9 anos) completaram todas as etapas do estudo; 72% dos encaminhados apresentavam algum grau de RD, sendo que normais e retinopatas tinham características comparáveis. Foram subdivididos em 4 grupos segundo a presença ou ausência de cada complicação. Não houve diferença na distribuição quanto a sexo, raça e escolaridade. O tempo de DM foi maior naqueles com ND+RD quando comparados ao grupo sem RD, com ou sem ND (14,8±6,4 vs. 7,2±5,3 e 9,2±5,6 anos, p< 0,05, respectivamente). A freqüência de fumantes e dislipidemia auto-referida, o IMC, glicemia e hemoglobina glicosilada não diferiram entre os grupos. Pacientes com ambas as complicações tinham pressão arterial média maior que os grupos sem RD, com ou sem ND (147±23 vs. 128±20 e 118±18mmHg, p< 0,05, respectivamente). Indivíduos com ND, independente da presença de RD, apresentaram razão Albumina/Creatinina (A/C) mais alta que os grupos sem ND (p< 0,05); o grupo com apenas RD não diferiu do grupo normal. Os maiores níveis de A/C do grupo com ambas as complicações não diferiram estatisticamente dos nefropatas sem RD. 80% dos pacientes nefropatas apresentavam RD, enquanto 74% dos retinopatas tinham também ND (c2= 6,39; p< 0,05). Detectou-se correlação significante entre estas complicações (r= 0,47; p< 0,05), assim como a concordância entre seus graus, resultando em kappa de 0,154 (IC 95%: 0,031-0,276; p< 0,01). A hipertensão se associou aos casos de maior gravidade, caracterizados pela concomitância de RD e ND. A ocorrência de uma complicação microvascular na ausência de outra sugere a existência de fatores etiopatogênicos órgão-específicos. Nossos dados indicam correspondência entre os graus de lesão renal e retiniana na microangiopatia do DM2. Pacientes com ND se associam a maior risco de lesões retinianas, de modo que o encontro de A/C alterada em paciente diabético requer, ainda que na faixa microalbuminúrica, a investigação de acometimento retiniano.

Human fructosamine-3-kinase: purification, sequencing, substrate specificity, and evidence of activity in vivo

Nonenzymatic glycation appears to be an important factor in the pathogenesis of diabetic complications. Key early intermediates in this process are fructosamines, such as protein-bound fructoselysines. In this report, we describe the purification and characterization of a mammalian fructosamine-3-kinase (FN3K), which phosphorylates fructoselysine (FL) residues on glycated proteins, to FL-3-phosphate (FL3P). This phosphorylation destabilizes the FL adduct and leads to its spontaneous decomposition, thereby reversing the nonenzymatic glycation process at an early stage. FN3K was purified to homogeneity from human erythrocytes and sequenced by means of electrospray tandem mass spectrometry. The protein thus identified is a 35-kDa monomer that appears to be expressed in all mammalian tissues. It has no significant homology to other known proteins and appears to be encoded by genomic sequences located on human chromosomes 1 and 17. The lability of FL3P, the high affinity of FN3K for FL, and the wide distribution of FN3K suggest that the function of this enzyme is deglycation of nonenzymatically glycated proteins. Because the condensation of glucose and lysine residues is an ubiquitous and unavoidable process in homeothermic organisms, a deglycation system mediated by FN3K may be an important factor in protecting cells from the deleterious effects of nonenzymatic glycation. Our sequence data of FN3K are in excellent agreement with a recent report on this enzyme by Delpierre et al. (Diabetes 49:1627-1634, 2000).