Increased plasma adiponectin concentrations are associated with microangiopathy in type 1 diabetic subjects

The role of adiponectin and its receptor signaling in ocular inflammation-associated diseases

Ocular inflammation-associated diseases are leading causes of global visual impairment, with limited treatment options. Adiponectin, a hormone primarily secreted by adipose tissue, binds to its receptors, which are widely distributed throughout the body, exerting powerful physiological regulatory effects. The protective role of adiponectin in various inflammatory diseases has gained increasing attention in recent years. Previous studies have confirmed the presence of adiponectin and its receptors in the eyes. Furthermore, adiponectin and its analogs have shown potential as novel drugs for the treatment of inflammatory eye diseases. This article summarizes the evidence for the interplay between adiponectin and inflammatory eye diseases and provides new perspectives on the diagnostic and therapeutic possibilities of adiponectin.

Adiponectin: A "Friendly adipokine" in Diabetic Retinopathy?

PURPOSE

Adiponectin has also been associated with diabetic retinopathy, a diabetic microvascular complication. However, the mechanism of action of adiponectin in retinopathy is still under investigation. This review summarizes emerging evidence on the association with diabetic retinopathy in type 2 diabetes.

METHODS

We reviwed papers from 2004 to 2022 and included studies related to retinopathy and its association with blood and intraocular adiponectin in type 2 diabetes.

RESULTS

Most of the studies analyzed in this review suggested an association between the diabetic retinopathy progression and intraocular, serum, or plasma adiponectin levels. Increased levels of adiponectin contributed to the development of the disease in diabetic patients. In a minority of studies, it was indicated an inversely proportional relationship between adiponectin concentration and diabetic retinopathy severity.

CONCLUSION

The high levels of adiponectin in diabetic patients may be related to the decrease in renal clearance. Under this situation, if the predominant isoform is globular adiponectin, this may explain the retinopathy progression, considering a pro-inflammatory response induced by this isoform. However, the actions of adiponectin in diabetic retinopathy pathophysiology are still controversial.

Potential Protective Function of Adiponectin in Diabetic Retinopathy

Adiponectin, one of the most ubiquitous adipokines found in the blood, plays a major role in glucolipid metabolism and energy metabolism and regulation. In recent years, a growing body of research indicates that adiponectin also plays a significant role in diabetic retinopathy. In the present review, we specifically address the protective effects of adiponectin on the development and progression of diabetic retinopathy through improvement in insulin resistance, alleviation of oxidative stress, limiting of inflammation, and prevention of vascular remodeling, with the aim to explore new potential approaches and targets for the prevention and treatment of diabetic retinopathy.

Mendelian randomization analyses in ocular disease: a powerful approach to causal inference with human genetic data

Ophthalmic epidemiology is concerned with the prevalence, distribution and other factors relating to human eye disease. While observational studies cannot avoid confounding factors from interventions, human eye composition and structure are unique, thus, eye disease pathogenesis, which greatly impairs quality of life and visual health, remains to be fully explored. Notwithstanding, inheritance has had a vital role in ophthalmic disease. Mendelian randomization (MR) is an emerging method that uses genetic variations as instrumental variables (IVs) to avoid confounders and reverse causality issues; it reveals causal relationships between exposure and a range of eyes disorders. Thus far, many MR studies have identified potentially causal associations between lifestyles or biological exposures and eye diseases, thus providing opportunities for further mechanistic research, and interventional development. However, MR results/data must be interpreted based on comprehensive evidence, whereas MR applications in ophthalmic epidemiology have some limitations worth exploring. Here, we review key principles, assumptions and MR methods, summarise contemporary evidence from MR studies on eye disease and provide new ideas uncovering aetiology in ophthalmology.

Association between Pediatric Adenovirus Infection and Type 1 Diabetes

Background: Viruses are among the inducers of type 1 diabetes (T1D) as they are implicated in the initiation of β-cell destruction. This study aimed to explore the link between adenoviruses’ infection, inflammatory biomarkers, and the development of T1D. Methods: The study population included 80 children with T1D and 40 healthy controls (2–16 years old). The T1D group was further clustered into two groups according to time of T1D diagnosis: a group of children who were diagnosed during the first year of life and a second group who were diagnosed after the first year of life. Adenovirus DNA, anti-adenovirus IgG, cytokines, and lipid profiles were screened in the different groups. The results were statistically assessed using one-way analysis of variance (ANOVA) and LSD t-test. Results: Positive adenovirus PCR was detected in 2.5% and 20% of normal and T1D children, respectively. Moreover, the positive PCR results for adenovirus were found significantly higher in the T1D group, who were diagnosed during the first year of life (33.4%), in comparison to those diagnosed after the first year of life (12%). Anti-adenoviruses IgG was found in 12.5% and 40% of healthy controls and diabetic children, respectively. Seropositive results were found to be higher in newly diagnosed children (46.7%) in comparison to those previously diagnosed with T1D (36%). Body mass index (BMI), IFN-γ, IL-15, adiponectin, lipid profile, and microalbuminuria were significantly increased in T1D adenoviruses-positive children compared to children who were negative for adenoviruses. Conclusions: Adenovirus infection could be among the contributing risk factors and may play a role in the induction of T1D in children.

Serum adipokine levels in patients with type 1 diabetes are associated with degree of obesity but only resistin is independently associated with atherosclerosis markers

PURPOSE

The role of adipokines in causing inflammation and insulin resistance in normal weight and obese patients is generally well studied. However, there are often conflicting results regarding their levels in type 1 diabetes mellitus (T1DM) patients and their relationship to micro- and macrovascular disease. We therefore investigated which serum adipokine levels are independently associated with markers of early atherosclerosis and microvascular complications in patients with T1DM.

METHODS

A cross-sectional study was performed in the Diabetes Outpatient Clinic of Hippokrateion General Hospital, Thessaloniki, Greece. Sixty T1DM patients (30 females, mean age 38.8 ± 10.6 years, mean diabetes duration 17.4 ± 9.9 years) were included. Plasma adiponectin, leptin, and resistin, carotid artery intima media thickness (cIMT), and arterial stiffness (pulse wave velocity, PWV/SpygmoCor CP System and Mobil-O-Graph 24 h PWA) were assessed.

RESULTS

Leptin and resistin levels were significantly higher in overweight and obese patients (p = 0.002 and p = 0.039, respectively). Adiponectin was the only adipokine negatively correlated with BMI (r_s =  - 0.41, p = 0.001). We report a bivariate association between serum adiponectin levels and retinopathy (p = 0.007). Resistin was the only adipokine that showed significant correlation with systolic (r_s = 0.42, p = 0.001) and diastolic (r_s = 0.29, p = 0.024) hypertension and PWV (p = 0.035).

CONCLUSIONS

Serum adipokine levels demonstrate similar bivariate associations with anthropometric variables in patients with T1DM to those in normal weight subjects. Although microvascular complications are associated with serum adipokine levels by bivariate analysis, only resistin, an inflammatory marker, is independently associated with arterial stiffness in patients with T1DM.

Crosstalk relationship between adiponectin receptors, PPAR-γ and α-adrenoceptors in renal vasculature of diabetic WKYs

Hypoadiponectinemia is associated with renal dysfunctions. Irbesartan and pioglitazone activate Peroxisome proliferator-activated gamma receptor (PPAR-γ) as partial and full agonists. We investigated a crosstalk interaction and synergistic action between adiponectin receptors, PPAR-γ agonists in attenuating renal hemodynamics to adrenergic agonists in diabetic Wistar Kyoto rats (WKY). Streptozotocin (40 mg/kg) was used to induce diabetes, whereas, pioglitazone (10 mg/kg/day), irbesartan (30 mg/kg/day) administered orally for 28 days and adiponectin intraperitoneally (2.5 μg/kg/day) for last 7 days. Metabolic and plasma samples were analyzed on days 0, 8, 21, and 28. During the acute study (day 29), renal vasoconstrictor actions to adrenergic agonists and angiotensin-II were determined. Diabetic WKYs had lower plasma adiponectin, higher creatinine clearance, urinary and fractional sodium excretion but were normalized to a greater extent in pioglitazone and adiponectin combined treatment. Responses to intra-renal administration of adrenergic agonists including noradrenaline (NA), phenylephrine (PE), methoxamine (ME), and angiotensin-II (ANG-II) were larger in diabetic WKY, but significantly blunted with adiponectin treatment in diabetic WKYs to 35-40%, and further reduced by 65-70% in combination with pioglitazone. Attenuation to ANG-II responses in adiponectin and combination with irbesartan was 30-35% and 75-80%, respectively (P < 0.05). Pharmacodynamically, a crosstalk interaction exists between PPAR-γ, adiponectin receptors (adipo R1 & R2), alpha adrenoceptors, and angiotensin-I (ATI) receptors in the renal vasculature of diabetic WKYs. Exogenously administered adiponectin with full PPAR-γ agonist substantially attenuated renal hemodynamics and improved excretory functions, signifying their renoprotective action. Additionally, a degree of synergism exists between adiponectin and pioglitazone to a large extent compared to combination therapy with irbesartan (partial PPAR-γ agonist) in attenuating the renal vascular receptiveness to adrenergic agonists.

Serum and aqueous humor adiponectin levels correlate with diabetic retinopathy development and progression

PURPOSE

To compare adiponectin (APN) levels in the serum and aqueous humor (AH) and evaluate their association with the development/progression of diabetic retinopathy (DR).

METHODS

Diabetic patients with (group 3; n = 59) and without (group 2; n = 39) DR and age- and sex-matched normal subjects (group 1; n = 35) were compared. Duration of diabetes, body mass index, serum HbA1c, vascular endothelial growth factor (VEGF), APN, pentraxin 3 (PTX3), platelet derived growth factor (PDGF), intercellular adhesion molecule-1 (ICAM-1), and APN were measured and analyzed.

RESULTS

One hundred and thirty-three participants were included. Compared to patients without diabetes, diabetic patients with DR had significantly elevated average serum APN levels (5.99±3.89 μg/ml versus 3.51±1.44 μg/ml, P = 0.002) and average AH APN levels (10.94±11.74 ng/ml versus 3.65±3.33 ng/ml, P<0.001). Serum APN was significantly correlated with AH APN (R = 0.512, P<0.001) and AH VEGF (R = 0.202, P = 0.020). The log serum APN was significantly correlated with intraocular cytokines, including log APN, log VEGF, log ICAM, log leptin, log PTX3, log PDGF, angiopoietin, C-reactive protein, and interleukins (IL)-5 and IL-10 (P<0.001, P = 0.020, P<0.001, P<0.001, P = 0.001, P<0.001, P = 0.008, P = 0.009, P<0.001, and P = 0.046, respectively). Log serum VEGF showed a significant correlation only with log AH VEGF (P = 0.001). Multivariate logistic analysis was performed to evaluate the association of DR progression and cytokine concentrations; log Serum APN and log AH APN showed good correlation with the DR progression in each model.

CONCLUSIONS

AH APN levels correlated well with DR development and progression. Serum APN could be a better marker for estimating intraocular cytokines, including both intraocular APN and VEGF concentrations in clinical field, than serum VEGF in DR patients.

Plasma total adiponectin and changes in renal function in a cohort from the community: the prospective Data from an Epidemiological Study on the Insulin Resistance Syndrome study

BACKGROUND

High adiponectin levels are associated with diabetic nephropathy. Nevertheless, it is not known whether plasma adiponectin is associated with renal function decline in the general population. We evaluated whether adiponectin concentrations were associated with changes in renal function in a community cohort, the Data from an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) study.

METHODS

Plasma adiponectin concentrations were measured in a random sample of 3284 people from the DESIR study, a 9-year prospective cohort from the general population. Data were analysed for three endpoints during follow-up: incidence of Stage 3 chronic kidney disease (CKD); the Kidney Disease: Improving Global Outcomes (KDIGO) criterion 'certain drop in eGFR' and rapid kidney function decline [estimated glomerular filtration rate (eGFR) slope steeper than -3 mL/min/1.73 m2/year].

RESULTS

After exclusion of participants with an eGFR <60 mL/min/1.73 m2 at baseline and those with type 2 diabetes or impaired fasting glycaemia at any time during follow-up (remaining n = 2174), there was a 113% higher risk for a rapid decline in kidney function in participants with adiponectin above the third tertile (T3) versus below the first tertile (T1) (Ptrend = 0.004) and a 53% higher risk for kidney function decline as defined by the KDIGO criterion (Ptrend = 0.04). In a cross-sectional analysis, adiponectin was positively associated with urinary albumin:creatinine ratio at baseline (P = 0.009).

CONCLUSIONS

In a healthy cohort from the general population, higher levels of plasma adiponectin were associated with decreased renal function at baseline and at follow-up. This result is similar to what is observed in people with diabetic nephropathy, in contrast with animal models of nephropathy.

The Role of Adiponectin in Maintaining Metabolic Homeostasis

BACKGROUND

Adiponectin is an adipocyte-derived cytokine closely associated with obesity, altered body adipose tissue distribution, insulin resistance, and cardiovascular diseases.

INTRODUCTION

Evidence from animal and human studies demonstrate that adiponectin plays an important role in the regulation of glucose and lipid metabolism. Adiponectin increases insulin sensitivity and improves systemic lipid metabolism. Although research efforts on adiponectin mostly aim towards its endocrine functions, this adipocyte-derived molecule also has profound autocrine and paracrine functions.

CONCLUSION

In this review, our aim is to discuss the role of adiponectin in maintaining metabolic homeostasis and its association with cardiovascular health. The proper identification of these roles is of great importance, which has the potential to identify a wealth of novel targets for the treatment of diabetes and related cardio-metabolic diseases.

Association and biomarker potential of elevated serum adiponectin with nephropathy among type 1 and type 2 diabetics: A meta-analysis

Background

Managing nephropathy associated with diabetes mellitus warrant investigation of relevant biomarkers in predicting this condition. Adiponectin (ADP) may hold promise as a biomarker for diabetic nephropathy (DN). In this study, we examine associations of ADP with DN by meta-analyzing relevant literature. We also examined the predictive potential of ADP and estimate progression of DN.

Methods

Multi-database literature searches and serial omissions of articles yielded 13 studies for inclusion in the meta-analysis. We compared ADP levels between controls/ normoalbuminuria and cases with micro- and macroalbuminuria (MI and MA, respectively) as well as MI versus MA using standardized mean differences (SMD). Associations of ADP with DN were indicated with the P-value considered significant at ≤ 0.05. Subgrouping was based on diabetes type (1 and 2). Predictive potential of ADP was explored with AUC (area under the curve) derived from Receiver Operating Characteristic curve analysis.

Results and conclusion

At high P-values of <10⁻⁵, overall and subgroup outcomes indicated ADP associations with DN (up to SMD = 1.89–2.26, respectively). However, heterogeneity of the initial SMD effects (up to I² = 99%) warranted examination of their sources which with the Galbraith plot method, either eliminated or reduced their heterogeneity, signifying combinability of the studies. This feature along with consistency of significant associations, robust outcomes and significant AUC values provide good evidence of the associative and predictive roles of ADP in DN.

T-cadherin gene variants are associated with nephropathy in subjects with type 1 diabetes

Background

High plasma adiponectin levels are associated with diabetic nephropathy (DN). T-cadherin gene (CDH13) variants have been shown to be associated with adiponectin levels. We investigated associations between allelic variations of CDH13 and DN in subjects with type 1 diabetes.

Methods

Two CDH13 polymorphisms were analysed in 1297 Caucasian subjects with type 1 diabetes from the 'Survival Genetic Nephropathy' (SURGENE) (n = 340, 10-year follow-up), 'Genesis France-Belgium' (GENESIS) (n = 501, 5-year follow-up for n = 462) and 'Génétique de la Néphropathie Diabétique' (GENEDIAB) (n = 456, 9-year follow-up for n = 283) cohorts. Adiponectin levels were measured in plasma samples from GENESIS and GENEDIAB cohorts.

Results

Pooled analysis of GENEDIAB and GENESIS studies showed that baseline plasma adiponectin levels were higher in subjects with established/advanced DN at inclusion (P < 0.0001) and in subjects who developed end-stage renal disease (ESRD) at follow-up (P < 0.0001). The minor allele of rs3865188 was associated with lower adiponectin levels (P = 0.006). rs11646213 [odds ratio (OR) 1.47; 95% confidence interval (CI) 1.18-1.85; P = 0.0009] and rs3865188 (OR 0.71; 95% CI 0.57-0.90; P = 0.004) were associated with baseline prevalence of established/advanced DN. These polymorphisms were also associated with the risk of ESRD (0.006 < P < 0.03). The association between rs11646213 (but not rs3865188) and renal function remained significant after adjustment for plasma adiponectin. In SURGENE, rs11646213 [hazard ratio (HR) 1.69; 95% CI 1.01-2.71; P = 0.04] and rs3865188 (HR 0.74; 95% CI 0.55-0.99; P = 0.04) were associated with risk of renal events (defined as progression to more severe DN stages).

Conclusions

Plasma adiponectin levels are associated with the prevalence of DN and the incidence of ESRD in patients with type 1 diabetes. CDH13 polymorphisms are also associated with the prevalence and incidence of DN, and with the incidence of ESRD in these patients. The association between CDH13 and DN may be due to pleiotropic effects, both dependent and independent of plasma adiponectin levels.

A New Optimized Percutaneous Access System for CIPII

In recent years, continuous intraperitoneal insulin infusion (CIPII) has become a favored treatment alternative for patients with subcutaneous insulin resistance, mainly due to its ability of mimicking physiological conditions of insulin absorption. CIPII has been shown to improve glycemic control as well as to reduce hypoglycemic events and to lead to increased patient satisfaction and quality of life (QoL). Among CIPII delivery systems, Diaport stands out due to its low side effects, its demonstrated clinical efficacy and the potential for integration into closed-loop systems.

Review: adiponectin in retinopathy

Neovascular eye diseases are a major cause of blindness including retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration in which new vessel formation is driven by hypoxia or metabolic abnormalities affecting the fuel supply. White-adipose-tissue derived adipokines such as adiponectin modulate metabolic responses. Increasing evidence shows that lack of adiponectin may result in retinal neovascularization. Activation of the adiponectin pathway may in turn restore energy metabolism, to suppress the drive for compensatory but ultimately pathological neovessels of retinopathy. In this review, we will summarize our current knowledge of the role of adiponectin in eye diseases of premature infants, diabetic patients as well as the elderly. Further investigations in this field are likely to lead to new preventative approaches for these diseases.

Study of Adiponectin Level in Diabetic Adolescent Girls in Relation to Glycemic Control and Complication of Diabetes

AIM:

To study the relation between adiponectin level with glycemic control and complication of diabetes.

PATIENTS AND METHODS:

The study included 40 female adolescent type 1 diabetic patients and 40 healthy volunteers of the same age and sex. Blood sample was taken for assessment of glycosylated hemoglobin, lipid profile and adiponectine. Urine sample was taken for assessment of albumin/creatinine ratio.

RESULTS:

Diabetic patients had a significantly higher diastolic blood pressure, triglyceride, total cholesterol, LDL and adiponectin than controls. Patients with diabetes complication had a significant lower BMI and HDL. On the other hand, they had higher disease duration, total cholesterol, HbA1, albumin/creatinine ratio and adiponectin. Patients with microalbuminuria had a lower BMI, higher disease duration, diastolic blood pressure and adiponectin. Patients with diabetic retinopathy had higher disease duration, insulin dose, HbA1, microalbuminuria and adiponectin. Adiponectin in diabetic patients had a significant negative correlation with BMI and positive correlation with systolic blood pressure and microlabuminuria.

CONCLUSION:

Serum adiponectin level is high in adolescent type 1 diabetic girls. It can be used as a predictor of diabetes complications rather than a sensitive biochemical marker for glycemic control.

Adiponectin, Insulin Sensitivity and Diabetic Retinopathy in Latinos With Type 2 Diabetes

CONTEXT AND OBJECTIVE

Insulin resistance and chronic inflammation are key elements in the pathogenesis of type 2 diabetes. We hypothesized that similar mechanisms could have a role in the development of diabetic retinopathy (DR), an important microvascular complication in Latinos with type 2 diabetes.

DESIGN AND SETTING

A cross-sectional, family-based, observational cohort study.

PATIENTS

Latino subjects with type 2 diabetes (n = 507), ascertained in families via a proband with known diabetes duration of 10 years or more and/or with DR, were included.

MAIN OUTCOME MEASURES

Serum adiponectin was measured and insulin sensitivity was estimated using homeostasis model assessment of insulin resistance (HOMA-IR). DR was assessed by seven-field digital fundus photography and graded using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Scale (range of severity levels, 10-85).

RESULTS

Fasting adiponectin concentrations were elevated in patients with DR compared to those without (12.9 ± 0.5 vs 10.5 ± 0.5 μg/mL; P = .0004) and remained significant after adjusting for multiple covariates (age, gender, body mass index, glycosylated hemoglobin, diabetes duration, statin use, blood pressure, and renal function; P = .013 to .018). Adiponectin was also positively correlated with severity of DR in patients with nonproliferative DR (P < .0003), significant also after all covariate adjustments (P = .018). When the proliferative DR group was included, this relationship was attenuated by adjustments, possibly an influence of estimated glomerular filtration rate reduction in the proliferative DR group. HOMA-IR was not different in the DR and non-DR groups. Although elevated, adiponectin retained a typical inverse relationship with HOMA-IR in DR, similar to that seen in the non-DR group.

CONCLUSIONS

Serum adiponectin is elevated in DR, is positively correlated with DR severity in Latinos with type 2 diabetes, and maintains a relationship to insulin sensitivity. Adiponectin, whether as a marker or biological mediator, may play an important role in DR, which appears to be independent of its relationship to insulin sensitivity.

The progress in understanding and treatment of diabetic retinopathy

Diabetic retinopathy is the most frequently occurring complication of diabetes mellitus and remains a leading cause of vision loss globally. Its aetiology and pathology have been extensively studied for half a century, yet there are disappointingly few therapeutic options. Although some new treatments have been introduced for diabetic macular oedema (DMO) (e.g. intravitreal vascular endothelial growth factor inhibitors ('anti-VEGFs') and new steroids), up to 50% of patients fail to respond. Furthermore, for people with proliferative diabetic retinopathy (PDR), laser photocoagulation remains a mainstay therapy, even though it is an inherently destructive procedure. This review summarises the clinical features of diabetic retinopathy and its risk factors. It describes details of retinal pathology and how advances in our understanding of pathogenesis have led to identification of new therapeutic targets. We emphasise that although there have been significant advances, there is still a pressing need for a better understanding basic mechanisms enable development of reliable and robust means to identify patients at highest risk, and to intervene effectively before vision loss occurs.

Low serum adiponectin levels in children and adolescents with diabetic retinopathy

OBJECTIVE

The aim of this study was to elucidate the role of adiponectin, leptin, TNF-α and IL-6 on the early detection of the microvascular complications of type I diabetes.

MATERIALS AND METHODS

A total of 88 children were included in the study. There were 60 type I diabetic patients and 28 healthy control children.

RESULTS

The gender, age, weight, height, BMI and puberty status characteristics were similar in the patient and control groups (p>0.05). The serum leptin, TNF-α and IL-6 levels were similar between the patient and control groups (p>0.05) and the only difference was in the serum adiponectin level which was higher in the patient group (p:0.042). We also found no association between the adiponectin, leptin, TNF-α and IL-6 levels and diabetes duration (p>0.05). Leptin was high in the pubertal period (p:0.016), while adiponectin TNF-α and IL-6 levels were similar in the prepubertal and pubertal periods (p>0.05). The serum leptin level was high in microalbuminuria patients (p<0.041). The serum adiponectin, TNF-α, and IL-6 levels were not different in patients with and without microalbuminuria (p>0.05). The serum adiponectin level was lower in diabetic retinopathy patients (p:0.003), while the serum leptin level was higher (p:0.003). The TNF-α and IL-6 levels were similar in patients with and without retinopathy (p>0.05).

CONCLUSION

We found increased serum adinopectin levels in children and adolescents with type I diabetes mellitus and low levels in diabetic retinopathy patients. Patients with low serum adiponectin levels and high leptin levels should be more closely monitored for chronic complication development and better metabolic control should be aimed for.

Inverse Levels of Adiponectin in Type 1 and Type 2 Diabetes Are in Accordance with the State of Albuminuria

Aims. To investigate the behaviour of adiponectin (ApN) in patients with type 1 and type 2 diabetic nephropathy. Methods. ApN and inflammatory and other markers of the metabolic syndrome were compared across diabetes types, albumin excretion rate (AER), and creatinine clearance (CrCl) categories in 219 type 1 and type 2 diabetic patients. Results. Significant differences among ApN levels according to AER were found in both types of diabetes (F = 8.45, df = 2, P < 0.001). With the progression of albuminuria, ApN increased in type 1 and decreased in type 2 diabetes. Patients with decreased CrCl had higher ApN levels than those with normal CrCl in either type of diabetes (F = 12.7, df = 1, P < 0.001). The best model for ApN (R (2) = 0.9002) obtained from stepwise regression in type 1 diabetes included CrCl, BMI, WBC, CRP, and age, while in type 2 diabetes (R (2) = 0.2882) it included ppPG, LDL, and UA. Conclusion. ApN behaved differently in relation to albuminuria, increasing with its progression in type 1 diabetes and decreasing in type 2 diabetes. It was however increased in the subgroups with decreased CrCl in both types of diabetes. Albuminuria seems to be more important than renal insufficiency in the definition of ApN levels in type 1 and type 2 diabetes.

Elevated Systemic Neutrophil Count Is Associated with Diabetic Macroalbuminuria among Elderly Chinese

Background. This study investigated an association between systemic absolute neutrophil count (ANC) and albuminuria in elderly Chinese people. Methods. A cross-sectional study was conducted on 2265 participants attending a routine medical examination in Minhang District as part of a Platform of Chronic Disease program. Their drug history, waist circumference, height, blood pressure, fasting blood glucose, ANC, and urine albumin levels were recorded. This study conformed to the requirements of the STROBE statement. Results. Of the 2265 subjects, 1254 (55.4%) were diabetic and 641 (28.3%) had albuminuria. The mean ANC of patients with diabetes comorbid with macroalbuminuria was significantly higher than that of both the nondiabetic patients and patients with diabetes with lower levels of albuminuria; the latter 2 groups had statistically similar ANC. ANC significantly and positively correlated with levels of urine albumin. Based on multivariate analysis, with each 10(9)/L increase in ANC, the increase in rates of macroalbuminuria was significant but not in rates of albuminuria positivity. Based on areas under the receiver operating characteristic curve, ANC was the strongest factor predicting macroalbuminuria. Conclusions. Elevated ANC was associated with macroalbuminuria in diabetes, indicating that neutrophil-mediated inflammation may be involved in the exacerbation of albuminuria.

Intraperitoneal insulin infusion: treatment option for type 1 diabetes resulting in beneficial endocrine effects beyond glycaemia

Continuous intraperitoneal insulin infusion (CIPII) is a treatment option for patients with type 1 diabetes mellitus who fail to reach adequate glycaemic control despite intensive subcutaneous (SC) insulin therapy. CIPII has clear advantages over SC insulin administration in terms of pharmacokinetic and pharmacodynamic properties and has been shown to improve glycaemic regulation. Due to the delivery of insulin predominantly in the portal vein, as opposed to systemically, CIPII offers a unique research model to investigate the effects of insulin on endocrine and metabolic parameters in vivo. The aim of the present article is to provide an overview of the literature with respect to the effects of CIPII on glucose management, quality of life, complications and costs, with additional focus on metabolic and endocrine aspects. Finally, future use and research objectives are discussed.

Current trends in the monitoring and treatment of diabetic retinopathy in young adults

The diagnosis and treatment of diabetic retinopathy (DR) in young adults have significantly improved in recent years. Research methods have widened significantly, for example, by introducing spectral optical tomography of the eye. Invasive diagnostics, for example, fluorescein angiography, are done less frequently. The early introduction of an insulin pump to improve the administration of insulin is likely to delay the development of diabetic retinopathy, which is particularly important for young patients with type 1 diabetes mellitus (T1DM). The first years of diabetes occurring during childhood and youth are the most appropriate to introduce proper therapeutic intervention before any irreversible changes in the eyes appear. The treatment of DR includes increased metabolic control, laserotherapy, pharmacological treatment (antiangiogenic and anti-inflammatory treatment, enzymatic vitreolysis, and intravitreal injections), and surgery. This paper summarizes the up-to-date developments in the diagnostics and treatment of DR. In the literature search, authors used online databases, PubMed, and clinitrials.gov and browsed through individual ophthalmology journals, books, and leading pharmaceutical company websites.

Impact of high-/middle-molecular-weight adiponectin on the synthesis and regulation of extracellular matrix in dermal fibroblasts

Adiponectin has been shown to play a critical role in immunity. Recently, we reported that the adiponectin levels after allogeneic stem cell transplantation were higher in recipients with chronic graft-versus-host disease (cGVHD). However, the effects of adiponectin on extracellular matrix (ECM) and regulatory factors in dermal fibroblasts remain unclear. We compared the messenger RNA (mRNA) levels of collagen type1 (COL1A), fibronectin 1 (FN1), matrix metalloproteinase (MMP)1, MMP3, tissue inhibitor of metalloproteinase (TIMP)1, TIMP3, transforming growth factor-β (TGF-β), and TGF-β receptor 2 (TGF-βR2) in human normal dermal fibroblasts cultured with and without adiponectin, and we assessed the degree of synthesis of ECMs by immunofluorescent microscopy. Furthermore, we also assessed these mRNA levels after blocking of TGF-βR2. Adiponectin induced higher mRNA levels of FN1, MMP1, MMP3, TIMP1, TIMP3, and TGF-βR2 in a dose-dependent manner, but did not significantly affect COL1A or TGF-β. In addition, adiponectin was shown to upregulate FN1, MMPs, and TIMPs after blocking of TGF-βR2. Immunofluorescent microscopy revealed that adiponectin promoted a greater synthesis of ECMs than in the control in vitro. The finding that adiponectin upregulated ECM-associated factors might mean that high levels of adiponectin could modulate dermal fibrosis was observed in recipients with cGVHD. Further basic investigation is warranted to elucidate whether the adiponectin-pathway could be a target for the treatment of sclerotic cGVHD.

Clinical use of adiponectin as a marker of metabolic dysregulation

Adiponectin concentrations exhibit strong cross-sectional relationships with obesity, inflammation, and diabetes. Adiponectin concentrations have been extensively evaluated as epidemiologic markers of diabetes and cardiovascular disease risk. In the present review we will provide an overview of these epidemiologic relationships as the backdrop for an evaluation of the clinical applications of adiponectin measurements. These include using adiponectin as an indicator of need for preventive or therapeutic intervention, as a predictor of response to therapy, and as a marker of therapeutic effectiveness. These efforts are laying the groundwork for the transition of adiponectin measurements from the laboratory to the clinic.

Effects of fenofibrate on adiponectin expression in retinas of streptozotocin-induced diabetic rats

Adiponectin has been associated with increased risks of microvascular complications in diabetes; however, its role in the development of diabetic retinopathy (DR) is unknown. Fenofibrate is a lipid-lowering agent that has been shown to be capable of preventing DR progression. We investigated the expression of adiponectin and its receptors in DR and evaluated the effects of fenofibrate on their expression. The mRNA and protein levels of adiponectin and its receptors were elevated in retinas of streptozotocin-induced diabetic rats and were suppressed following fenofibrate treatment. Immunofluorescence staining demonstrated that adiponectin and adipoR1 were expressed in cells located within blood vessels, the retinal ganglion, and the inner nuclear layer. AdipoR1 was strongly expressed whereas adipoR2 was only weekly expressed in vascular endothelial cells. The in vitro experiments showed that adiponectin expression was induced by high glucose concentrations in RGC-5 and RAW264.7 cells and was suppressed following fenofibrate treatment. AdipoR1 and adipoR2 levels in RGC-5 cells were elevated in high glucose concentrations and suppressed by fenofibrate. Our results demonstrated that adiponectin may be a proinflammatory mediator in diabetic retinas and fenofibrate appears to modulate the expression of adiponectin and its receptors in diabetic retinas, effectively reducing DR progression.

Urinary adiponectin excretion rises with increasing albuminuria in type 1 diabetes

AIM

Urinary adiponectin (u-adiponectin) excretion has been suggested to reflect early glomerular damage. Inspired by this, we studied the levels of u-adiponectin in type 1 diabetic patients with different levels of urinary albumin excretion (UAE).

METHODS

U-adiponectin was analysed by ELISA in type 1 diabetic patients: Fifty-eight with normoalbuminuria (<30mg albumin/24h), 43 with persistent microalbuminuria (30-300mg/24h) and 44 with persistent macroalbuminuria (>300mg/24h). For comparison, a control group of 55 healthy individuals was included.

RESULTS

U-adiponectin increased with increasing levels of UAE (p<0.01). U-adiponectin median (interquartile range): Normoalbuminuria 0.38 (0.14-1.31), microalbuminuria 1.12 (0.20-2.68), macroalbuminuria 9.20 (1.10-23.35) and controls 0.09 (0.06-0.24) μg/g creatinine. Levels were unrelated to sex, age, cholesterol, diastolic BP and BMI. U-adiponectin was weakly associated with increasing systolic BP and HbA1c (r(2)<0.1, p<0.05), but strongly related to increasing UAE (r(2)=0.57, p<0.001) and decreasing eGFR (r(2)=0.26, p<0.001). The relationship between UAE and u-adiponectin was significant in all groups and independent of eGFR, BMI, BP and HbA1c. Furthermore, u-adiponectin was associated with markers of tubular damage (p<0.01).

CONCLUSION

U-adiponectin rises with increasing levels of UAE in patients with type 1 diabetes. This is in accordance with the hypothesis that loss of adiponectin may reflect glomerular and/or tubular damage.

Mechanisms of diabetic complications

It is increasingly apparent that not only is a cure for the current worldwide diabetes epidemic required, but also for its major complications, affecting both small and large blood vessels. These complications occur in the majority of individuals with both type 1 and type 2 diabetes. Among the most prevalent microvascular complications are kidney disease, blindness, and amputations, with current therapies only slowing disease progression. Impaired kidney function, exhibited as a reduced glomerular filtration rate, is also a major risk factor for macrovascular complications, such as heart attacks and strokes. There have been a large number of new therapies tested in clinical trials for diabetic complications, with, in general, rather disappointing results. Indeed, it remains to be fully defined as to which pathways in diabetic complications are essentially protective rather than pathological, in terms of their effects on the underlying disease process. Furthermore, seemingly independent pathways are also showing significant interactions with each other to exacerbate pathology. Interestingly, some of these pathways may not only play key roles in complications but also in the development of diabetes per se. This review aims to comprehensively discuss the well validated, as well as putative mechanisms involved in the development of diabetic complications. In addition, new fields of research, which warrant further investigation as potential therapeutic targets of the future, will be highlighted.

Adiponectin in renal disease--a review of the evidence as a risk factor for cardiovascular and all-cause mortality

Adiponectin, an adipokine, was discovered in 1995. The initial evidence led to the study of adiponectin as a determinant of insulin sensitivity and blood glucose levels. The literature then evolved to reports of the inverse association of adiponectin with incident Type 2 diabetes mellitus and coronary heart disease. Shortly thereafter, reports of a positive association with heart failure and mortality appeared and were replicated. We review here the basic science evidence and clinical studies of the role of renal function and kidney disease as a determinant of adiponectin.

Adiponectin and arterial stiffness in youth with type 1 diabetes: the SEARCH for diabetes in youth study

Persons with type 1 diabetes are at increased risk of developing vascular disease. Adiponectin concentrations may play an intermediate role in this process. We sought to determine whether adiponectin is correlated with vascular stiffness in adolescents with type 1 diabetes. Plasma adiponectin, pulse wave velocity (PWV), augmentation index (AIx-75), and brachial distensibility (BrachD) were collected in 225 adolescents. Outcomes were evaluated by sex, and regression models were used to determine whether adiponectin was an independent determinant of arterial stiffness. Males had lower adiponectin levels and stiffer vessels (lower BrachD, p < 0.01) than females. Unadjusted correlations revealed that adiponectin was correlated with BrachD (p < 0.01) but not PWV and AIx-75. After adjustment, adiponectin was not a significant predictor of BrachD. The most consistent predictors of increased stiffness were age, male sex, blood pressure, obesity, and total cholesterol (p < 0.05). Adiponectin's contributions to arterial stiffness appear to be masked by other cardiovascular risk factors in persons with type 1 diabetes.

Serum adiponectin concentration is a positive predictor of all-cause and cardiovascular mortality in type 1 diabetes

BACKGROUND

Adiponectin is widely regarded as an anti-atherogenic, antioxidant and anti-inflammatory molecule. However, adiponectin concentration is paradoxically increased in individuals with type 1 diabetes, in whom it is positively associated with adverse clinical outcomes.

OBJECTIVE

To explore the association between serum adiponectin concentration and mortality outcomes in adults with type 1 diabetes.

DESIGN

Multicentre prospective cohort study.

SETTING

Primary and tertiary care.

SUBJECTS

Finnish adults with type 1 diabetes (n= 2034). Main outcome measures.  All-cause and cardiovascular mortality. Independent predictors of mortality were determined using the Cox and the Fine and Gray competing risks proportional hazards models.

RESULTS

During a median of 11 years of follow-up, there were 173 deaths (8.5%, 1.0 per hundred person-years). Adiponectin was linearly associated with all-cause mortality [Cox model: hazard ratio (HR) 1.02, 95% confidence interval (CI) 1.01-1.03, P<0.001] and cardiovascular mortality (Fine and Gray model: HR 1.02, 95% CI 1.00-1.04, P=0.035); patients with the highest adiponectin concentrations had the shortest survival. The mortality risk associated with adiponectin was independent of glycaemic and lipid control, pre-existing cardiovascular disease, markers of inflammation and the presence and severity of kidney disease.

CONCLUSIONS

Although adiponectin is generally considered to be a protective molecule, increased concentrations of adiponectin in type 1 diabetes are independently associated with all-cause and cardiovascular mortality. Moreover, the fact that this association was observed for the first time in patients with normal urinary albumin levels, who have few comorbidities, suggests that adiponectin is specifically linked with vascular damage in type 1 diabetes.

Serum adipokine levels in type 1 diabetic patients: association with carotid intima media thickness

BACKGROUND

Adipokines are markers of insulin resistance and play a role in the atherosclerotic process. The association of adipokines with the macrovascular complications of type 1 diabetes mellitus (DM) needs to be determined. The aim of this study was to measure serum adiponectin, leptin, and resistin levels in type 1 DM patients and investigate their relationship with carotid intima media thickness (CIMT), a clinical marker of atherosclerosis.

METHODS

Seventy-five type 1 DM patients and 115 sex and age-matched healthy controls were included in the study. Serum adiponectin, leptin, and resistin levels were measured by the enzyme-linked immunosorbent assay (ELISA method). CIMT was assessed by Doppler ultrasonography.

RESULTS

Adiponectin levels in diabetics were higher (25.8±14.8 μg/mL vs. 5.5±7.3 μg/mL; P<0.0001) and leptin levels were lower than controls (9.4±6.2 ng/mL vs. 12.8±8.6 ng/mL; P=0.01). Resistin levels were also higher in the diabetic group compared to controls (2.1±1.4 ng/mL vs. 1.6±0.8 ng/mL; P=0.04). Adiponectin was correlated negatively with CIMT (r=-0.24, P=0.03), age (r=-0.30, P=0.02), BMI (r=-0.33, P=0.02), waist-to-hip ratio (WHR) (r=-0.38, P=0.01) and positively with creatinine (r=0.44, P=0.004). Leptin levels were correlated with total cholesterol (r=0.53, P=0.01) and high-density lipoprotein (HDL) (r=0.67, P=0.001). Resistin was correlated with CIMT (r=0.24, P=0.03) and systolic blood pressure (r=0.48, P=0.009). Multivariate analysis revealed resistin and creatinine to be independent predictors of CIMT among adiponectin, leptin, resistin, WHR, glycosylated hemoglobin (HbA1c), and creatinine.

CONCLUSIONS

Increased adiponectin correlates negatively and resistin positively with CIMT in type 1 diabetic patients, but adjusting for other known predictors reveals only resistin to be associated with subclinical atherosclerosis in this group of patients.

In hemodialysis, adiponectin, and pro-brain natriuretic peptide levels may be subjected to variations in body mass index

Adiponectin exerts cardiovascular protective actions, although some studies have shown the opposite. In hemodialysis, obese subjects display lower mortality rates despite hypoadiponectinemia, while higher adiponectin concentrations correlate with an elevated cardiovascular risk in nonobese subjects. The aim of the study is to suggest that adiponectin level variations are associated with differences in the body mass index (BMI). The interplay between adiponectin and pro-brain natriuretic peptide (Pro-BNP) levels may vary according to body fat mass. Fifty-two chronic hemodialysis patients were divided into three groups. Group A, BMI<25 (n=20); Group B, BMI 25 to 30 (n=21), and Group C, BMI>30 (n=11). Diabetics: Group A 10%; Group B 6 29%; Group C 55%, P=0.027. Determinations: Adiponectin, Pro-BNP, insulin, insulin resistance (HOMA), troponin T, nutritional status, ultrafiltration rates, C-reactive protein (CRP), vascular accesses, and echocardiography. Group A: adiponectinemia positively and significantly correlated with Pro-BNP, CRP, and troponin T. As BMI increased, adiponectin, Pro-BNP, and malnutrition significantly decreased, while insulin, HOMA, and ultrafiltration rates significantly increased. Cardiac restriction was significantly higher in obese patients. In all groups, Pro-BNP and troponin T displayed a strong positive correlation. In low-BMI subjects, high Pro-BNP and adiponectin, low myocardial restriction, and worse nutritional status were prevalent. In obesity, hypoadiponectinemia stimulates cardiac remodeling, cardiac hypertrophy, and decreased stretching, rendering Pro-BNP levels low despite high ultrafiltration rates. Thus, adiponectin correlates inversely with BMI, probably playing different cardiovascular roles as BMI changes.

Relationship between ADIPOQ gene, circulating high molecular weight adiponectin and albuminuria in individuals with normal kidney function: evidence from a family-based study

AIMS/HYPOTHESIS

Insulin resistance is associated with reduced serum adiponectin and increased albuminuria levels. Thus, one would anticipate an inverse relationship between circulating adiponectin and albuminuria. However, several studies have described a 'paradoxical' elevation of serum adiponectin in patients with elevated albuminuria. These findings may have been confounded by the presence of diseases and related treatments known to affect circulating adiponectin and albuminuria. We therefore studied the relationship between circulating adiponectin and albuminuria in the absence of such confounders.

METHODS

To this purpose, the relationship between adiponectin isoforms and albumin:creatinine ratio (ACR) was investigated in a family-based sample of 634 non-diabetic untreated white individuals with normal kidney function. We also investigated whether the two variables share a common genetic background and addressed the specific role of the gene encoding adiponectin on that background by genotyping several ADIPOQ single nucleotide polymorphisms (SNPs).

RESULTS

ACR was directly associated with high molecular weight (HMW) adiponectin isoform (p = 0.024). The two variables shared some genetic correlation (ρ(g) = 0.38, p = 0.04). ADIPOQ promoter SNP rs17300539 was associated with HMW adiponectin (p = 4.8 × 10(-5)) and ACR (p =0.0027). The genetic correlation between HMW adiponectin and ACR was no longer significant when SNP rs17300539 was added to the model, thus reinforcing the role of this SNP in determining both traits.

CONCLUSIONS/INTERPRETATION

Our study shows a positive, independent correlation between HWM adiponectin and ACR. ADIPOQ variability is associated with HMW adiponectin and ACR, and explains some of the common genetic background shared by these traits, thus suggesting that ADIPOQ and HMW adiponectin modulate albuminuria levels.

Hyperadiponectinemia is independent of kidney function, diabetes duration, and control in type 1 diabetic patients without microangiopathy

INTRODUCTION

High total adiponectin (ADPN) levels were reported in type 1 diabetes (T1D) and related to long diabetes duration and nephropathy. We studied whether ADPN and its specific isoforms were elevated in T1D without microangiopathy and whether they were related to kidney function.

MATERIALS AND METHODS

Total, high, medium, and low molecular weight ADPN and insulin levels were measured in 47 consecutive normoalbuminuric, normotensive T1D patients without retinopathy and in 47 age-, sex-, and body mass index-matched controls. Glomerular filtration rate was estimated by (51)Cr-EDTA plasma clearance.

RESULTS

Total and high molecular weight ADPN ratio were higher in T1D patients than in controls. ADPN levels were not related to anthropometric measures, whereas they were in controls. In T1D, ADPN levels were not related to glycosylated hemoglobin, diabetes duration, or glomerular filtration rate. Peripheral insulin levels were higher in T1D patients than in controls, but they were not related to ADPN levels. In controls, insulin levels were positively related to total ADPN.

CONCLUSION

In T1D without microangiopathy, high ADPN levels could not be related to anthropometric diabetes parameters, kidney function, or high insulin levels. The nature of this elevation remains unknown.

Intensifying glycaemic control with insulin reduces adiponectin and its HMW isoform moderately in type 2, but not in type 1, diabetes

INTRODUCTION

As the impact of diabetes control was not tested on adiponectin (ADPN) levels, this study was designed to assess whether or not controlling hyperglycaemia can affect ADPN.

PATIENTS AND METHODS

A total of 15 T1D and 48 T2D patients with HbA(1c) greater than 10% were studied at the time of hospitalization for uncontrolled diabetes. Total, and high-, medium- and low-molecular-weight (HMW, MMW, LMW) ADPN were measured at the time of study inclusion, on days 1 and 8, and at 1, 3 and 6 months after insulin treatment.

RESULTS

While diabetes control improved, total and HMW APDN decreased on days 1 and 8, but remained steady thereafter in T2D patients. In T1D patients, ADPN levels remained unchanged throughout the study.

CONCLUSION

Glycaemic control with insulin reduces ADPN in T2D patients in the short-term, but was ineffective in T1D.

Resistance training improves cardiovascular risk factors in obese women despite a significative decrease in serum adiponectin levels

Increased circulating adiponectin and insulin sensitivity are usually observed after body fat loss induced by a weight-loss diet. Progressive resistance training (PRT) without a concomitant weight-loss diet significantly decreases visceral fat, thus improving insulin sensitivity. Therefore, the purpose of this study was to ascertain the effects of combined 16-week PRT and weight-loss diet on circulating adiponectin and insulin sensitivity index. Thirty-four obese (BMI: 30-40 kg/m(2)) women, aged 40-60 year, were randomized to three groups: a control group (C; n = 9); a diet group (WL; n = 12) with a caloric restriction of 500 kcal/d; and a diet plus resistance training group (WL+RT; n = 13) with the same caloric restriction as group WL and a 16-week supervised whole body PRT of two sessions/week. Both WL and WL+RT groups showed similar decreases in body mass (-6.3% and -7.7%) and visceral fat (-19.9% and -20.5%). WL resulted in an expected increase in circulating levels of adiponectin (P = 0.07) and insulin sensitivity. However, circulating total adiponectin decreased (P < 0.05) in WL+RT group, whereas an improvement in different cardiovascular risk factors (insulin sensitivity, low-density lipoprotein cholesterol (LDL-C), etc.) was observed. In conclusion, in obese women a 16-week combined PRT and weight-loss diet is accompanied by significant improvements in different cardiovascular risk factors in spite of a significant decrease of circulating adiponectin.

Increased arterial stiffness in children and adolescents with type 1 diabetes: no association between arterial stiffness and serum levels of adiponectin

OBJECTIVE

Type 1 diabetes is associated with an increased risk of atherosclerosis. Adiponectin serum levels correlate inversely with cardiovascular disease in adults. The aim of this study was to examine associations between arterial stiffness indices and serum adiponectin concentrations in children and adolescents with type 1 diabetes and to study the impact of metabolic control.

SUBJECTS AND METHODS

We evaluated arterial stiffness, distensibility, and compliance in 93 children and adolescents with type 1 diabetes and correlated the data with clinical parameters and HbA1c levels. The control group comprised 85 matched healthy children. Serum levels of adiponectin in children with diabetes were measured by enzyme-linked immunoassay and correlated with arterial stiffness indices.

RESULTS

Arterial stiffness was significantly increased in children and adolescents with type 1 diabetes (aged 13.0 +/- 3.8 yr) compared with matched healthy children (p = 0.03). Arterial stiffness was elevated in males with type 1 diabetes compared with females (p = 0.023). Arterial distensibility was significantly lower in children with diabetes compared with healthy controls (p = 0.025). Arterial stiffness, distensibility, and compliance did not correlate with diabetes duration, level of HbA1c, or serum cholesterol. Adiponectin concentrations in children and adolescents with diabetes were significantly elevated compared with normal values based on gender, age, and body mass index. We found no significant associations between arterial stiffness indices and adiponectin levels in children with type 1 diabetes.

CONCLUSIONS

Children and adolescents with type 1 diabetes had increased arterial stiffness and reduced arterial distensibility and arterial compliance. However, no associations between arterial functional alterations and adiponectin concentrations were seen.

Association of ADIPOQ genetic variants and plasma adiponectin isoforms with the risk of incident renal events in type 2 diabetes

BACKGROUND

Adiponectin levels are high in cases of diabetic nephropathy, but it remains unclear whether these high levels are a cause or a consequence of the disease. We investigated the possible association of polymorphisms in the adiponectin gene and baseline adiponectin levels with the incidence of renal events in subjects with type 2 diabetes.

METHODS

We studied three adiponectin polymorphisms (-11391G > A, +45T > G and +276G > T) in 3086 subjects with type 2 diabetes and high levels of albumin excretion from the diabetes, hypertension, microalbuminuria or proteinuria, cardiovascular events and ramipril (DIABHYCAR) trial. Baseline concentrations of total adiponectin and of adiponectin isoforms were determined in cases with incident renal events and in controls matched for sex, age, body mass index (BMI) and adiponectin genotype. We used another cohort of type 2 diabetes patients-the survie, diabète de type 2 et génétique(SURDIAGENE) study (n = 1004)-for the replication of genetic data.

RESULTS

In DIABHYCAR, the -11391A and +45G alleles were associated with a higher incidence of renal events [hazard ratio (HR) = 1.73; 95% confidence interval (CI), 1.10-2.71; and HR = 1.68; 95% CI, 1.14-2.47, respectively]. The haplotype containing susceptibility alleles, -11391A/+45G/+276G, was more frequent in cases with renal events (5.1% vs. 1.9% in those without, P = 0.005). In SURDIAGENE, the -11391A/+45G/+276G haplotype was also associated with renal events (5.6% vs. 1.9% in those without, P = 0.03). In DIABHYCAR, all isoforms were more abundant in subjects carrying the -11391A or +45G alleles. Medium- (MMW) and low-molecular weight (LMW) isoforms were more abundant in cases with renal events.

CONCLUSIONS

In subjects with type 2 diabetes and early renal dysfunction, adiponectin gene variants are determinants of the renal risk. The -11391A and +45G alleles may affect renal risk by leading to high circulating adiponectin concentrations, at least those of MMW and LMW isoforms.

Cytokine and cytokine-like inflammation markers, endothelial dysfunction, and imbalanced coagulation in development of diabetes and its complications

CONTEXT

Recent developments indicate that pathophysiological mechanisms leading to beta-cell damage, insulin resistance, and the vascular complications of diabetes include an activation of the inflammation cascade, endothelial dysfunction, and procoagulant imbalance. Their circulating biomarkers may therefore provide opportunities for early diagnosis and targets for novel treatments.

EVIDENCE

Circulating biomarkers of these pathways such as TNFalpha, IL-6, C-reactive protein (CRP) (inflammation), vascular cellular adhesion molecule-1, interstitial cellular adhesion molecule-1, E-selectin, von Willebrand factor (endothelial dysfunction), plasminogen activator inhibitor-1, fibrinogen, P-selectin (procoagulant state), and adiponectin (antiinflammation) may be associated with development of both type 1 and type 2 diabetes and some studies, particularly in type 2 diabetes, have demonstrated that certain biomarkers may have independent predictive value. Similarly studies have shown that these biomarkers may be associated with development of diabetic nephropathy and retinopathy, and again, particularly in type 2 diabetes, with cardiovascular events as well. Finally, the comorbidities of diabetes, namely obesity, insulin resistance, hyperglycemia, hypertension and dyslipidemia collectively aggravate these processes while antihyperglycemic interventions tend to ameliorate them.

CONCLUSIONS

Increased CRP, IL-6, and TNFalpha, and especially interstitial cellular adhesion molecule-1, vascular cellular adhesion molecule-1, and E-selectin are associated with nephropathy, retinopathy, and cardiovascular disease in both type 1 and type 2 diabetes. Whereas further work is needed, it seems clear that these biomarkers are predictors of increasing morbidity in prediabetic and diabetic subjects and should be the focus of work testing their clinical utility to identify high-risk individuals as well as perhaps to target interventions.

A single nucleotide polymorphism alters the sequence of SP1 binding site in the adiponectin promoter region and is associated with diabetic nephropathy among type 1 diabetic patients in the Genetics of Kidneys in Diabetes Study

OBJECTIVE

The adiponectin promoter single nucleotide polymorphism (SNP) -11391G/A is found to be associated with nephropathy in type 1 diabetic (T1D) patients among Danish, but not French, Finnish, and Swedish populations. In the present study, we identified the binding sites for transcriptional factors in the adiponectin promoter region and also evaluated the association between adiponectin promoter polymorphisms and diabetic nephropathy (DN) in T1D patients.

MATERIALS AND METHODS

Three adiponectin promoter SNPs, including -11377C/G, -11391G/A, and -11426A/G, were genotyped with dynamic allele-specific hybridization. The subjects included 1177 American T1D patients (622 females/555 males) with or without DN. All patients are of European descent and selected from the Genetics of Kidneys in Diabetes (GoKinD) study.

RESULTS

We identified four binding sites of transcriptional stimulatory protein (SP1) in the adiponectin putative promoter and found that the G allele of SNP -11377C/G altered the sequence for one of the SP1 binding sites. This polymorphism was significantly associated with DN in female T1D patients (P=.022, OR=1.352, 95% CI=1.044-1.752). Further analyses indicated the common diplotype (haplotypic genotype) H1/H1, constructed with SNPs -11377C/G and -11391G/A, was significantly associated with DN in females (P=.013), while the association of another diplotype H1/H2 with DN in females was of borderline significance (P=.071).

CONCLUSIONS

The present study thus provides the first evidence that SNP -11377C/G alters the sequence in one of the SP1 binding sites in the adiponectin promoter region. This polymorphism, together with another promoter SNP -11391G/A, may confer susceptibility to the development of DN in T1D patients among the GoKinD population.

Metabolic phenotypes, vascular complications, and premature deaths in a population of 4,197 patients with type 1 diabetes

OBJECTIVE

Poor glycemic control, elevated triglycerides, and albuminuria are associated with vascular complications in diabetes. However, few studies have investigated combined associations between metabolic markers, diabetic kidney disease, retinopathy, hypertension, obesity, and mortality. Here, the goal was to reveal previously undetected association patterns between clinical diagnoses and biochemistry in the FinnDiane dataset.

RESEARCH DESIGN AND METHODS

At baseline, clinical records, serum, and 24-h urine samples of 2,173 men and 2,024 women with type 1 diabetes were collected. The data were analyzed by the self-organizing map, which is an unsupervised pattern recognition algorithm that produces a two-dimensional layout of the patients based on their multivariate biochemical profiles. At follow-up, the results were compared against all-cause mortality during 6.5 years (295 deaths).

RESULTS

The highest mortality was associated with advanced kidney disease. Other risk factors included 1) a profile of insulin resistance, abdominal obesity, high cholesterol, triglycerides, and low HDL(2) cholesterol, and 2) high adiponectin and high LDL cholesterol for older patients. The highest population-adjusted risk of death was 10.1-fold (95% CI 7.3-13.1) for men and 10.7-fold (7.9-13.7) for women. Nonsignificant risk was observed for a profile with good glycemic control and high HDL(2) cholesterol and for a low cholesterol profile with a short diabetes duration.

CONCLUSIONS

The self-organizing map analysis enabled detailed risk estimates, described the associations between known risk factors and complications, and uncovered statistical patterns difficult to detect by classical methods. The results also suggest that diabetes per se, without an adverse metabolic phenotype, does not contribute to increased mortality.

Adiponectin and catecholamine concentrations during acute exercise in children with type 1 diabetes

OBJECTIVE

Adiponectin, an adipokine secreted by the adipocyte, is inversely related to adiposity and directly related to insulin sensitivity. In type 1 diabetes mellitus (T1DM), however, data thus far are contradictory. We investigated the relationship between adiponectin and exercise inT1DM.

METHODS

Forty-nine children (14.5 +/- 2.0 yr, range 8-17 yr) with T1DM on an insulin pump were studied during two 75-min exercise sessions with and without continuation of the basal rate within 4 wk. Adiponectin and epinephrine concentrations were measured before and during exercise.

RESULTS

Mean preexercise adiponectin concentration was 11.2 +/- 4.7 mg/L (range 2.7-23.0 mg/L) with a mean absolute difference of 1.7 mg/L between the 2 d. Adiponectin concentrations did not change meaningfully during exercise (mean change: -0.1 +/- 1.2 mg/L; p = 0.17). Adiponectin correlated inversely with body mass index percentile (p = 0.02) but not with age, gender, duration of diabetes, hemoglobin A1c, or preexercise glucose. However, those with higher baseline adiponectin concentrations were less likely to become hypoglycemic during exercise, 36% becoming hypoglycemic when baseline adiponectin concentration was <10 mg/L, 42% when 10 to <15 mg/L, and 15% when > or =15 mg/L (p = 0.02). Baseline epinephrine concentrations were not associated with adiponectin, and in those whose nadir glucose was < or =100 mg/dL, there was no correlation between epinephrine response and adiponectin (p = 0.16).

CONCLUSIONS

Adiponectin concentrations are stable from day to day, are not affected by acute exercise or metabolic control, and vary inversely with adiposity. Higher adiponectin concentration appears to be associated with a decrease in hypoglycemia risk during exercise. Further studies are needed to examine whether adiponectin protects against exercise-induced hypoglycemia by directly enhancing the oxidation of alternate fuels.

Serum adiponectin and progression of diabetic nephropathy in patients with type 1 diabetes

OBJECTIVE

The purpose of this study was to elucidate whether serum adiponectin is associated with progression of diabetic nephropathy in type 1 diabetic patients.

RESEARCH DESIGN AND METHODS

This was a prospective follow-up study as a part of the nationwide Finnish Diabetic Nephropathy Study; 1,330 type 1 diabetic patients were followed for 5.0 +/- 2.2 years. Patients were divided at baseline into three groups according to their urinary albumin excretion rate (AER) in three consecutive overnight or 24-h urine collections: 818 patients with normoalbuminuria (AER <20 microg/min), 216 patients with microalbuminuria (20 microg/min <or= AER < 200 microg/min), and 296 patients with macroalbuminuria (AER >or=200 microg/min). Progression of albuminuria was the main outcome. Adiponectin was measured by a time-resolved immunofluorometric assay, and the values were log-transformed and adjusted for age, BMI, and sex before analysis.

RESULTS

Progression either to the next albuminuria level or to end-stage renal disease (ESRD) occurred in 193 patients. No difference in adiponectin concentrations was observed between progressors and nonprogressors in patients with normoalbuminuria or microalbuminuria. In the patients with macroalbuminuria, progression to ESRD was associated with higher adiponectin in the entire group (23.4 +/- 17.1 vs. 16.0 +/- 8.5 mg/l, P < 0.001) and in men (P < 0.001) and women (P < 0.001) separately. Progression to ESRD was also associated with systolic blood pressure, insulin dose, A1C, serum cholesterol, serum triglycerides, AER, and estimated glomerular filtration rate (eGFR). When these covariates were inserted in a Cox regression analysis, A1C, triglycerides, eGFR, and adiponectin were significantly associated with progression from macroalbuminuria.

CONCLUSIONS

Increased serum adiponectin levels predict the progression from macroalbuminuria to ESRD in type 1 diabetic patients.

Effects of high levels of glucose on the steroidogenesis and the expression of adiponectin receptors in rat ovarian cells

BACKGROUND

Reproductive dysfunction in the diabetic female rat is associated with altered folliculogenesis and steroidogenesis. However, the molecular mechanisms involved in the reduction of steroid production have not been described. Adiponectin is an adipocytokine that has insulin-sensitizing actions including stimulation of glucose uptake in muscle and suppression of glucose production in liver. Adiponectin acts via two receptor isoforms - AdipoR1 and AdipoR2 - that are regulated by hyperglycaemia and hyperinsulinaemia in liver and muscle. We have recently identified AdipoR1 and AdipoR2 in rat ovary. However, their regulation in ovaries of diabetic female rat remains to be elucidated.

METHODS

We incubated rat primary granulosa cells in vitro with high concentrations of glucose (5 or 10 g/l) + or - FSH (10-8 M) or IGF-1 (10-8 M), and we studied the ovaries of streptozotocin-induced diabetic rats (STZ) in vivo. The levels of oestradiol and progesterone in culture medium and serum were measured by RIA. We used immunoblotting to assay key steroidogenesis factors (3beta HSD, p450scc, p450 aromatase, StAR), and adiponectin receptors and various elements of signalling pathways (MAPK ERK1/2 and AMPK) in vivo and in vitro. We also determined cell proliferation by [3H] thymidine incorporation.

RESULTS

Glucose (5 or 10 g/l) impaired the in vitro production in rat granulosa cells of both progesterone and oestradiol in the basal state and in response to FSH and IGF-1 without affecting cell proliferation and viability. This was associated with substantial reductions in the amounts of 3beta HSD, p450scc, p450 aromatase and StAR proteins and MAPK ERK1/2 phosphorylation. In contrast, glucose did not affect the abundance of AdipoR1 or AdipoR2 proteins. In vivo, as expected, STZ treatment of rats caused hyperglycaemia and insulin, adiponectin and resistin deficiencies. Plasma progesterone and oestradiol levels were also reduced in STZ rats. However, the amounts of 3beta HSD and p450 aromatase were the same in STZ rat ovary and controls, and the amounts of StAR and p450scc were higher. Streptozotocin treatment did not affect adiponectin receptors in rat ovary but it increased AMPK phosphorylation without affecting MAPK ERK1/2 phosphorylation.

CONCLUSION

High levels of glucose decrease progesterone and oestradiol production in primary rat granulosa cells and in STZ-treated rats. However, the mechanism that leads to reduced ovarian steroid production seems to be different. Furthermore, adiponectin receptors in ovarian cells are not regulated by glucose.