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Innovative biomarkers are required to manage type 2 diabetic patients (T2DM). We focused our study on miR-126-3p and miR-21-5p levels, as biomarkers of endothelial function and inflammation. MiRNAs levels were measured in plasma from 107 healthy subjects (CTR) and 193 diabetic patients (T2DM), 76 without (T2DM NC) and 117 with (T2DM C) complications. When diabetic complication were analysed as a whole, miR-126-3p and miR-21-5p levels declined significantly from CTR to T2DM NC and T2DM C patients. When miRNAs levels were related to specific complications, significantly higher miR-21-5p levels (0.46 ± 0.44 vs. 0.26 ± 0.33, p < 0.001) and significant lower miR-126-3p levels (0.21 ± 0.21 vs. 0.28 ± 0.22, p = 0.032) were found in T2DM with previous major cardiovascular events (MACE) vs. all the others T2DM patients. To confirm these results we focused on circulating angiogenic cells (CACs) from a subgroup of 10 CTR, 15 T2DM NC and 15 T2DM patients with MACE. CACs from T2DM patients expressed higher miR-21-5p and lower miR-126-3p levels than CACs from CTR. Furthermore, CACs from T2DM + MACE showed the highest levels of miR-21-5p. Circulating miR-21-5p and miR-126-3p emerge as dynamic biomarkers of systemic inflammatory/angiogenic status. Their expression levels in CACs from T2DM with MACE suggest a shift from a proangiogenic to a proinflammatory profile.

Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS). Increased levels of ADMA cause impaired vasodilation, leading to endothelial dysfunction and a higher risk for cardiovascular events. In patients with a chronic kidney disease, increased ADMA levels are reported to play a role in the pathogenesis of accelerated atherosclerosis and are an independent risk marker leading to end-stage renal disease and mortality. Circulating ADMA is metabolized by the action of dimethylarginine dimethylamino hydrolase (DDAH) and DDAH2 isoform is the most prevalent in tissues expressing endothelial NOS. DDAH and NOS are co-expressed in the same kidney regional sites supporting the hypothesis that a strict and specific regulation of intracellular ADMA levels is crucial for NO generation in the kidney. Starting from these findings, the study aims to investigate the role of DDAH2 gene promoter polymorphism at position -1151 A/C in determining the levels of ADMA in type 2 diabetic patients (T2DM) with chronic renal impairment., Methods: Three groups of carefully selected subjects of both sexes were enrolled and compared. The first group (control subjects) comprised 286 non-diabetic subjects (mean age 55.8 ± 11.4 years), the second group (T2DM uncomplicated subjects) was made up of 322 T2DM subjects without complications (mean age 64.9 ± 9.6 years) whereas the third group (T2DM CRF subjects) included 110 T2DM patients with chronic renal impairment. The rs805304 DDAH2-1151 A/C promoter polymorphism was determined by a polymerase chain reaction-restriction fragment length polymorphism approach. Results T2DM CRF subjects showed significant increased plasma levels of ADMA with respect to those of T2DM uncomplicated subjects and control subjects (0.51 versus 0.39 versus 0.37 μmol/L, P = 0.002, respectively). Analysis of variance showed an interaction between DDAH2-1151 C carrier and groups on ADMA plasma levels (F = 4.36; P < 0.05). ADMA plasma levels were also dependent on groups (F = 4.96; P < 0.01)., Conclusions: Our work demonstrates that rs805304 DDAH2-1151 polymorphism plays a central role in determining ADMA in diabetic renal impairment, where patients with DDAH2-1151 C carriers showed the highest ADMA levels. This unfavourable genetic profile is highlighted by pathological kidney conditions such as diabetic CRF. These findings could open new insights on the pathways involving ADMA/DDAH/NOS in the development and progression of chronic renal impairment and therefore of the other micro- macrovascular diabetic complications.

Mitochondrial dysfunction has been implicated in rare and common forms of type 2 diabetes (T2DM). Additionally, rare mitochondrial DNA (mtDNA) mutations have been shown to be causal for T2DM pathogenesis. So far, many studies have investigated the possibility that mtDNA variation might affect the risk of T2DM, however, when found, haplogroup association has been rarely replicated, even in related populations, possibly due to an inadequate level of haplogroup resolution. Effects of mtDNA variation on diabetes complications have also been proposed. However, additional studies evaluating the mitochondrial role on both T2DM and related complications are badly needed. To test the hypothesis of a mitochondrial genome effect on diabetes and its complications, we genotyped the mtDNAs of 466 T2DM patients and 438 controls from a regional population of central Italy (Marche). Based on the most updated mtDNA phylogeny, all 904 samples were classified into 57 different mitochondrial sub-haplogroups, thus reaching an unprecedented level of resolution. We then evaluated whether the susceptibility of developing T2DM or its complications differed among the identified haplogroups, considering also the potential effects of phenotypical and clinical variables. MtDNA backgrounds, even when based on a refined haplogroup classification, do not appear to play a role in developing T2DM despite a possible protective effect for the common European haplogroup H1, which harbors the G3010A transition in the MTRNR2 gene. In contrast, our data indicate that different mitochondrial haplogroups are significantly associated with an increased risk of specific diabetes complications: H (the most frequent European haplogroup) with retinopathy, H3 with neuropathy, U3 with nephropathy, and V with renal failure.

OBJECTIVE--To explore the possibility that oscillating glucose may outweigh A1C levels in determining the risk for cardiovascular diabetes complications. RESEARCH DESIGN AND METHODS--A euinsulinemic hyperglycemic clamp at 5, 10, and 15 mmol/l glucose was given in increasing steps as a single "spike" or oscillating between basal and high levels over 24 h in normal subjects and type 2 diabetic patients. Flow-mediated dilatation, a marker of endothelial function, and plasma 3-nitrotyrosine and 24-h urinary excretion rates of free 8-iso PGF2α, two markers of oxidative stress, were measured over 48 h postclamp. RESULTS--Glucose at two different levels (10 and 15 mmol/l) resulted in a concentration-dependent fasting blood glucose-independent induction of both endothelial dysfunction and oxidative stress in both normal and type 2 diabetic patients. Oscillating glucose between 5 and 15 retool/l every 6 h for 24 h resulted in further significant increases in endothelial dysfunction and oxidative stress compared with either continuous 10 or 15 mmol/l glucose. CONCLUSIONS--These data suggest that oscillating glucose can have more deleterious effects than constant high glucose on endothelial function and oxidative stress, two key players in favoring cardiovascular complications in diabetes. Concomitant vitamin C infusion can reverse this impairment. Diabetes 57: 1349-1354, 2008 [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the hypothesis that kidney function is an independent determinant of lipoprotein(a) concentrations in people with diabetes. Account of related studies; Research design and methods; Results and discussion.