Effects of exenatide on microvascular reactivity in patients with type 2 diabetes and coronary artery disease: A randomized controlled study.

OBJECTIVE: We studied the effect of the GLP-1RA exenatide on skin microvascular function in patients with T2DM and CAD. METHODS: Thirty-five patients with T2DM, CAD, and HbA1C 42-86 mmol/mol were randomized to treatment with exenatide or conventional non-GLP-1-based therapy for 12 weeks. Skin microvascular function was examined in the forearm by LDF and iontophoretic application of acetyl choline and SNP, and by PORH at baseline and after 12 weeks. Blood samples for fasting plasma glucose, HbA1C, and lipid profile were collected. RESULTS: At 12 weeks, patients on exenatide showed reductions in HbA1C (from 63.5 ± 13 to 60.7 ± 14 mmol/mol, p = .065), body weight (from 92.6 ± 16 to 89 ± 16 kg, p < .001), and systolic blood pressure (from 141 ± 13 to 134 ± 16 mm Hg, p < .05) as compared to the conventionally treated group. There were no significant changes in skin microvascular function between or within the two groups at follow-up. CONCLUSIONS: Three months' daily treatment with the GLP-1RA exenatide in T2DM patients with CAD showed no significant effects on skin microvascular function or blood glucose control, while this study confirms a reduction in body weight and blood pressure by exenatide, as compared to conventional antidiabetic drug treatment.

Altered Vascular Reactivity to Circulating Angiotensin II in Familial Hypercholesterolemia.

ABSTRACT: We have previously shown increased vascular reactivity to angiotensin (Ang) II in familial combined hyperlipidemia. However, this has not been well studied in familial hypercholesterolemia (FH), a condition with incipient endothelial dysfunction. This study aimed to examine microvascular and macrovascular responses to Ang II in FH. Therefore, we investigated the effects of a 3-hour infusion of Ang II on blood pressure and forearm skin microvascular function in 16 otherwise healthy patients with FH and matched healthy controls. Skin microvascular hyperemia was studied by laser Doppler fluxmetry during local heating. Microvascular resistance was determined by the ratio of mean arterial pressure to microvascular hyperemia. Macrovascular reactivity was assessed by changes in brachial blood pressure. Compared with the controls, the FH group had increased baseline systolic blood pressure (127 ± 14 vs. 115 ± 12 mm Hg; P = 0.02), while systolic blood pressure responses were similar (+24 ± 9 vs. +21 ± 7 mm Hg; P = 0.26) after 3 hours of Ang II infusion. At baseline, there were no group differences in microvascular hyperemia or resistance. However, after 3 hours of Ang II infusion, heat-induced microvascular hyperemia was less pronounced in FH (126 ± 95 vs. 184 ± 102 arbitrary units; P = 0.01), while microvascular resistance during heat-induced hyperemia was increased (1.9 ± 0.9 vs. 0.9 ± 0.8, P = 0.01), as compared to controls. Both these responses were further pronounced 1 hour after stopping Ang II. In conclusion, despite similar blood pressure responses to Ang II in the FH group and controls, microvascular dilatation capacity was impaired in the FH group, indicating endothelial dysfunction. These findings and increased microvascular resistance may lead to hypertension and microvascular complications in FH.

Changes in microparticle profiles by vitamin D receptor activation in chronic kidney disease - a randomized trial.

BACKGROUND: Microparticles (MPs) are biomarkers and mediators of disease through their expression of surface receptors, reflecting activation or stress in their parent cells. Endothelial markers, ICAM-1 and VCAM-1, are implicated in atherosclerosis and associated with cardiovascular risk. Chronic kidney disease (CKD) patients have endothelial dysfunction and high levels of endothelial derived MPs. Vitamin D treatment has been reported to ameliorate endothelial function in CKD patients. We aimed to examine cell specific MP profiles and concentrations of MPs expressing the atherosclerotic markers ICAM-1 and VCAM-1 after treatment with paricalcitol in patients with CKD stage 3-4. METHODS: Sub-study of the previously reported SOLID trial where 36 patients were randomly assigned to placebo, 1 or 2 µg paricalcitol, for 12 weeks. MPs were measured by flow cytometry after labelling with antibodies against endothelial (CD62E), platelet (CD62P, CD41, CD154) leukocyte (CD45) and vascular (CD54, CD106) markers. RESULTS: Patients had a mean age of 65 years with a mean eGFR of 40 mL/min/1.73m2. Concentrations of ICAM-1 positive MPs were significantly reduced by treatment (repeated measures ANOVA p = 0.04). Repeated measures MANOVA of concentrations of endothelial, platelet and leukocyte MPs showed sustained levels in the 2 µg treatment group (p = 0.85) but a decline in the 1 µg (p = 0.04) and placebo groups (p = 0.005). CONCLUSIONS: Treatment with paricalcitol reduces concentrations of ICAM-1 positive MPs. This is accompanied by sustained concentrations of all cell specific MPs in the 2 µg group, and decreasing concentrations in the other groups, possibly due to a more healthy and reactive endothelium with paricalcitol treatment.

Treating endothelial dysfunction with vitamin D in chronic kidney disease: a meta-analysis.

BACKGROUND: Vitamin D deficiency is common in patients with chronic kidney disease (CKD), and is associated with endothelial dysfunction and cardiovascular disease. We performed a meta-analysis to assess the effect of vitamin D treatment on flow mediated vasodilation (FMD) in CKD patients. METHODS: PubMed/Medline, Web of Science, Embase and Cochrane trials and reviews were searched systematically for randomized controlled trials (RCT:s) using any vitamin D compound, at any stage of CKD, with FMD as outcome. Fixed and random effects models were performed using the standardized mean difference effect size post treatment for each trial. Heterogeneity was assessed by I2 statistics. RESULTS: 4 trials were included, comprising 305 patients. One used both 1 and 2 µg for two intervention groups and was therefore split in two during the analysis. Patients in the included trials had a mean age of 44-65 years and were all in CKD 3 to 4. One study used cholecalciferol, the others all used paricalcitol as treatment. Study duration was 12-16 weeks. Intervention with vitamin D was associated with ameliorated FMD (STANDmean ES 0.78, 95% CI 0.55-1.01) in a fixed model. Heterogeneity was substantial (I2 = 84%). Secondary analysis with random model analysis also showed significant results. CONCLUSIONS: Short term intervention with vitamin D is associated with improvements in endothelial function, as measured by FMD. This indicates positive effects of vitamin D on vascular disease in CKD. Limitations of this meta-analysis are the small number of studies performed, and the short duration of intervention.

The expression of microvesicles in the blood of patients with Graves' disease and its relationship to treatment.

OBJECTIVE: Graves' disease (GD) is an autoimmune disease characterized by the presence of circulating autoantibodies against thyroid-stimulating hormone (TSH) receptor. Despite extensive research, the pathogenic mechanisms remain unclear. Immune responses associated with the disease may lead to cell activation/apoptosis and the release of microvesicles (MVs) into the circulation. MVs can display biological activities which may aggravate GD further. We studied immune mechanisms in GD by investigating the numbers and phenotype of circulating MVs in patients before and after antithyroid therapy with thiamazole. PATIENTS AND MEASUREMENTS: Samples were obtained from 15 patients with GD in the acute phase of hyperthyroidism and following 17-26 months treatment and 14 healthy controls. MVs from platelets, endothelial cells and monocytes exposing inflammation/activation markers (P-selectin, CD40 ligand, E-selectin and HMGB1) and MVs containing nuclear molecules were measured with flow cytometry. RESULTS: Patients had elevated baseline values of MVs (P < 0·001 for all types of MVs), while the levels decreased during thiamazole treatment (P < 0·05 for all types of MVs). The majority of MV populations remained, however, significantly higher in patients after treatment compared to levels in controls. CONCLUSIONS: GD patients have elevated levels of MVs that carry molecules with potential biological activities. MVs are significantly reduced after antithyroid treatment with thiamazole but still higher compared to levels in healthy controls. Assessment of MV levels and pattern may therefore provide additional information on underlying immune disturbances not obtained by measurements of hormone levels alone.

Severely impaired microvascular reactivity in diabetic patients with an acute coronary syndrome.

BACKGROUND: Microvascular function is impaired in patients with stable coronary artery disease. The aim was to study microvascular function in patients with diabetes and acute coronary syndrome (ACS). METHODS: Microvascular function was evaluated in 83 patients by laser Doppler fluxmetry (LDF) [PU; perfusion unit, median (interquartile range)] measuring resting LDF and peak LDF following a six min heating of the skin to 44 °C at the foot, respectively. All patients with ACS and without previously known diabetes underwent oral glucose tolerance test. Thirty-nine patients with type 2 diabetes mellitus free from coronary artery disease served as controls. RESULTS: Peak LDF was significantly (P = 0.03) lower in patients with ACS and diabetes (n = 22; 72 (52)) and diabetes without coronary artery disease (n = 39; 69 (51)) as compared to patients with ACS without diabetes (n = 46; 97 (60)), and patients without ACS (n = 15; 140 (121)), respectively. Patients with ACS (n = 68) had significantly (P = 0.04) lower peak LDF (92 (49)) as compared to patients without ACS (n = 15) (140 (121)). CONCLUSION: Microvascular reactivity is severely impaired in patients with diabetes and ACS. Diabetes has a major influence on microvascular function in patients with coronary artery disease.

Long-term clinical outcome in patients with acute coronary syndrome and dysglycaemia.

BACKGROUND: Diabetes and impaired glucose tolerance (IGT) are major risk factors for atherosclerosis including coronary artery disease (CAD). The present study's aim was to investigate the importance of glucose tolerance for long-term clinical outcome in patients with acute coronary syndrome (ACS). METHODS: A total 1062 consecutive patients, 781 men and 281 women, aged 32-80 years, admitted to the coronary care unit at Danderyd University Hospital, Stockholm, for ACS from 2006 to 2008 were included. At discharge, the patients were categorized according to an oral glucose tolerance test (OGTT) as having normal glucose tolerance (NGT), n = 295 (28%); impaired fasting glucose (IFG) and IGT, n = 299 (28%); diabetes discovered by OGTT, n = 156 (15%); or known diabetes at admission, n = 312 (29%). Mortality and reinfarction rates were studied during a mean follow-up time of 4.0 (±0.8) years. Clinical outcome data were obtained from the Swedish Coronary Angiography and Angioplasty Registry and the Swedish National Registry. RESULTS: There was significantly higher (p < 0.001) mortality within, 30 days, 1 and 3 years in patients with known diabetes as compared to the other groups. During the follow-up, 86 patients (28%) with known diabetes had reinfarction as compared to 36 patients (12%) with NGT and 79 patients (17%) with dysglycaemia (IFG, IGT and diabetes) discovered by OGTT. CONCLUSION: A majority (72% in this study) of patients admitted for ACS have disturbed glucose metabolism, including diabetes, with high prevalence of previously undiagnosed dysglycaemia. Both patients with known diabetes and dysglycaemia discovered by OGTT show a high risk for poor clinical prognosis.

Paricalcitol, Microvascular and Endothelial Function in Non-Diabetic Chronic Kidney Disease: A Randomized Trial.

BACKGROUND: Vitamin D deficiency, sympathetic activation and endothelial dysfunction are associated with increased cardiovascular risk in patients with chronic kidney disease (CKD). Studies have so far failed to establish the role of vitamin D and vitamin D receptor activator (VDRA) treatment in moderate CKD. This trial was designed to assess whether VDRA treatment can ameliorate sympathetic activation and macro- and microvascular dysfunction in non-diabetic patients with moderate CKD. METHODS: We conducted a randomized controlled double-blind trial using placebo, 1 or 2 µg of paricalcitol, a VDRA, for 3 months. We assessed muscle sympathetic nerve activity (MSNA) by microneurography, pulse wave velocity (PWV) by tonometry, flow mediated vasodilatation (FMD) by brachial ultrasound, skin microcirculation assessed by iontophoresis and capillary blood velocity (CBV) by videophotometric capillaroscopy. RESULTS: Thirty-six patients with a mean age of 65 years and mean estimated glomerular filtration rate of 40 ml/min/1.73 m2 were included. We found a significant decline in endothelial function after 3 months, except in the group receiving 2 µg of paricalcitol. The higher dose (2 µg) seemed to attenuate the decline in microvascular endothelial function, assessed by iontophoresis of acetylcholine (p=0.06 for all groups, p=0.65 for the 2 µg group) and for FMD (p=0.006 for all groups, p=0.54 for the 2 µg group). We found a borderline significance (p=0.05) for improved CBV in the treated groups. We found no significant changes between treatments in MSNA, PWV or albuminuria. CONCLUSIONS: Endothelial function declined significantly over 3 months in patients with moderate CKD, and this decline could be ameliorated by VDRA treatment (NCT01204528).

Clopidogrel Resistance after Minor Ischemic Stroke or Transient Ischemic Attack is Associated with Radiological Cerebral Small-Vessel Disease.

BACKGROUND: The objective of this study was to compare nonresponders (NR) and responders (R) to clopidogrel with respect to presence of microvascular and macrovascular pathology in a cohort of patients with recent minor ischemic stroke (IS) or transient ischemic attack (TIA). METHODS: Seventy-two patients treated with clopidogrel after IS or TIA were evaluated 1 month after onset. Platelet aggregation was measured by multiple electrode aggregometry (Multiplate). Nonresponse was defined according to recent consensus. The degree of cerebral small-vessel disease (cSVD) was evaluated on computed tomography scans of the brain using Fazekas scale for white matter changes. Carotid atherosclerosis was evaluated by ultrasound or computed tomography/magnetic resonance angiography. RESULTS: Twenty-two percent of patients were NR. Moderate to extensive cSVD was more common for NR than R, 56% versus 25%, odds ratio 3.9 (1.2-12), P = .03. Correspondingly, 39% of patients with cSVD were NR versus 14% of patients with no or mild cSVD. No differences were found between NR and R in prevalence or severity of carotid atherosclerosis. NR had higher platelet aggregation response than R after stimulation with arachidonic acid or thrombin receptor-activating peptide, indicating a general platelet hyperreactivity. In a univariate analysis, hypertension, previous IS, glucose intolerance, pulse pressure above median, and presence of moderate to extensive cSVD were associated with the NR phenotype. CONCLUSIONS: Nonresponsiveness to clopidogrel after minor IS or TIA is associated with radiological cSVD but not with carotid atherosclerosis. PRACTICE/IMPLICATIONS: Measurement of platelet function is warranted in patients with cSVD. Larger studies on alternative or tailored antiplatelet treatment for these patients should be initiated.

Glucose intolerance and insulin resistance as predictors of low platelet response to clopidogrel in patients with minor ischemic stroke or TIA.

The relation between high on-treatment platelet reactivity (HPR), and the level of glucose intolerance and insulin resistance (IR) was studied in clopidogrel-treated patients with minor ischemic stroke or TIA. The cohort consisted of 66 patients, 11 of which had known type 2 diabetes mellitus (DM). Platelet aggregation in whole blood (Multiplate™) and metabolic variables were measured 1 month after acute onset of neurological symptoms. Glucose tolerance was measured by Oral Glucose Tolerance Test (OGTT). IR was estimated by homeostasis model assessment HOMA-IR. Patients were categorized as "responders" (R) or "non-responders" (NR) to clopidogrel according to an established cut-off in platelet aggregation induced by adenosine diphosphate (ADP). In total, 14/66 (21%) patients were NR. Impaired glucose tolerance (IGT), impaired fasting glucose (IFG) or DM was seen in 13/14 NR (93%), while for R this was the case in 25/52 (48%), p = 0.001. The percentage of NR was 33% in patients with DM and 35% in patients with IGT or IFG. In the group with normal glucose tolerance (NGT) the percentage of NR was low, 4% (1/28). Fasting plasma glucose (f-PG) was higher for NR than for R, 6.0 (5.5-6.7) mM vs. 5.3 (5.0-6.0) mM, p = 0.023. Glycated hemoglobin (HbA1c) did not differ between NR and R. NR also had higher arachidonic acid-induced platelet aggregation than R, and a tendency towards higher aggregation induced by thrombin receptor agonist peptide (TRAP), indicating that HPR reflects a global platelet hyper-reactivity. HOMA-IR was calculated for 52 of the patients above without known diabetes, 9 of which were NR (17%). NR were significantly more insulin resistant than R, with median HOMA-IR 4.5 (3.0-7.4) compared to 2.1 (1.5-3.2) for R, p = 0.001. HOMA-IR and fasting plasma insulin were the only metabolic variables with significant relationships to ADP-induced platelet aggregation. The results suggest that HPR develops in the pre-diabetic phase. A metabolic disturbance with glucose intolerance and/or high level of IR was a pre-requisite for HPR in the tested cohort. Conversely, normal glucose tolerance combined with normal or mildly elevated HOMA-IR excluded HPR. NR are likely to constitute a high-risk group among patients with ischemic cerebrovascular disease. Measurement of f-PG or HbA1c is insufficient to identify NR, while OGTT and HOMA-IR are more predictive.

Acetylation and glycation of fibrinogen in vitro occur at specific lysine residues in a concentration dependent manner: a mass spectrometric and isotope labeling study.

Aspirin may exert part of its antithrombotic effects through platelet-independent mechanisms. Diabetes is a condition in which the beneficial effects of aspirin are less prominent or absent - a phenomenon called "aspirin resistance". We investigated whether acetylation and glycation occur at specific sites in fibrinogen and if competition between glucose and aspirin in binding to fibrinogen occurs. Our hypothesis was that such competition might be one explanation to "aspirin resistance" in diabetes. After incubation of fibrinogen in vitro with aspirin (0.8 mM, 24 h) or glucose (100 mM, 5-10 days), we found 12 modified sites with mass spectrometric techniques. Acetylations in the α-chain: αK191, αK208, αK224, αK429, αK457, αK539, αK562, in the ß-chain: ßK233, and in the γ-chain: γK170 and γK273. Glycations were found at ßK133 and γK75, alternatively γK85. Notably, the lysine 539 is a site involved in FXIII-mediated cross-linking of fibrin. With isotope labeling in vitro, using [(14)C-acetyl]salicylic acid and [(14)C]glucose, a labeling of 0.013-0.084 and 0.12-0.5 mol of acetylated and glycated adduct/mol fibrinogen, respectively, was found for clinically (12.9-100 µM aspirin) and physiologically (2-8 mM glucose) relevant plasma concentrations. No competition between acetylation and glycation could be demonstrated. Thus, fibrinogen is acetylated at several lysine residues, some of which are involved in the cross-linking of fibrinogen. This may mechanistically explain why aspirin facilitates fibrin degradation. We find no support for the idea that glycation of fibrin(ogen) interferes with acetylation of fibrinogen.

Reduced expression of OXPHOS and DNA damage genes is linked to protection from microvascular complications in long-term type 1 diabetes: the PROLONG study.

Type 1 diabetes is a chronic autoimmune disease requiring insulin treatment for survival. Prolonged duration of type 1 diabetes is associated with increased risk of microvascular complications. Although chronic hyperglycemia and diabetes duration have been considered as the major risk factors for vascular complications, this is not universally seen among all patients. Persons with long-term type 1 diabetes who have remained largely free from vascular complications constitute an ideal group for investigation of natural defense mechanisms against prolonged exposure of diabetes. Transcriptomic signatures obtained from RNA sequencing of the peripheral blood cells were analyzed in non-progressors with more than 30 years of diabetes duration and compared to the patients who progressed to microvascular complications within a shorter duration of diabetes. Analyses revealed that non-progressors demonstrated a reduction in expression of the oxidative phosphorylation (OXPHOS) genes, which were positively correlated with the expression of DNA repair enzymes, namely genes involved in base excision repair (BER) machinery. Reduced expression of OXPHOS and BER genes was linked to decrease in expression of inflammation-related genes, higher glucose disposal rate and reduced measures of hepatic fatty liver. Results from the present study indicate that at transcriptomic level reduction in OXPHOS, DNA repair and inflammation-related genes is linked to better insulin sensitivity and protection against microvascular complications in persons with long-term type 1 diabetes.

Skin microvascular reactivity correlates to clinical microangiopathy in type 1 diabetes: A pilot study.

AIM: The aim of this study was to investigate the correlation between skin microvascular reactivity and clinical microangiopathy in patients with type 1 diabetes. METHODS: We included 61 patients with type 1 diabetes, that is, 31 patients with and 30 without clinical microangiopathy, and 31 healthy controls. A microangiopathy scoring system was introduced for comparison of data between patients with microangiopathy. Responses to iontophoresis of acetylcholine and sodium nitroprusside were assessed by laser Doppler imaging. RESULTS: Patients with microangiopathy had reduced acetylcholine- and sodium nitroprusside-mediated flux in forearm skin microcirculation compared to healthy controls (p = 0.03 and p < 0.001, respectively, repeated measures analysis of variance), whereas no significant differences were found between patients without microangiopathy and controls. Skin reactivity was reduced in patients with microangiopathy compared to patients without microangiopathy: 1.43 ± 0.38 versus 1.59 ± 0.39 arbitrary units for acetylcholine-mediated peak flux and 1.44 ± 0.46 versus 1.74 ± 0.34 arbitrary units for sodium nitroprusside-mediated peak flux (p < 0.05 for both). A tendency of gradual decrease in acetylcholine and sodium nitroprusside responses was found in patients with increasing microangiopathy scores. CONCLUSION: We conclude that skin microvascular reactivity is associated with clinical microangiopathy in patients with type 1 diabetes. Impaired skin microvascular function in type 1 diabetes seems to be multifactorial and involves both endothelial-dependent and endothelial-independent pathways. We introduce a novel microangiopathy score that could easily be used in a clinical setting for comparison of patients with various degrees of microangiopathy.

High levels of endothelial and platelet microvesicles in patients with type 1 diabetes irrespective of microvascular complications.

INTRODUCTION: Patients with type 1 diabetes have high risk of developing microvascular complications, and microangiopathy contributes to premature cardiovascular disease in this population. The role that microvesicles (MVs) may play in the development of microangiopathy in type 1 diabetes remains unclear. MATERIALS AND METHODS: Plasma levels of endothelial MVs (EMVs) and platelet MVs (PMVs) in 130 patients with type 1 diabetes without microangiopathy, 106 patients with microangiopathy and 100 matched healthy controls were analyzed using flow cytometry. MV expression of procoagulant phosphatidylserine (PS) and proinflammatory high mobility group box-1 protein (HMGB1) was also assessed. RESULTS: Patients with type 1 diabetes had markedly elevated levels of EMVs and PS+ EMVs as well as PMVs and PS+ PMVs compared to healthy controls (p < .001 for all). Furthermore, HMGB1+ EMVs and HMGB1+ PMVs were significantly increased in patients (p < .001 for all). After adjusting for potential confounders, there were no clear differences between patients with or without microvascular complications for any of the MV parameters. CONCLUSION: Type 1 diabetes is a prothrombotic and proinflammatory disease state that, regardless of the presence of clinical microangiopathy, is associated with elevated levels of plasma MVs, in particular those of an endothelial origin. We have for the first time demonstrated that patients with type 1 diabetes have higher levels of HMGB1+ MVs. HMGB1 is an alarmin with potent proinflammatory effects that drive endothelial dysfunction, and it would therefore be of interest to further study the role of HMGB1+ MVs in the development of macrovascular complications in type 1 diabetes.

Increased Plasma Soluble Interleukin-2 Receptor Alpha Levels in Patients With Long-Term Type 1 Diabetes With Vascular Complications Associated With IL2RA and PTPN2 Gene Polymorphisms.

Type 1 diabetes (T1D) is largely considered an autoimmune disease leading to the destruction of insulin-producing pancreatic ß cells. Further, patients with T1D have 3-4-fold increased risk of developing micro- and macrovascular complications. However, the contribution of immune-related factors contributing to these diabetes complications are poorly understood. Individuals with long-term T1D who do not progress to vascular complications offer a great potential to evaluate end-organ protection. The aim of the present study was to investigate the association of inflammatory protein levels with vascular complications (retinopathy, nephropathy, cardiovascular disease) in individuals with long-term T1D compared to individuals who rapidly progressed to complications. We studied a panel of inflammatory markers in plasma of patients with long-term T1D with (n = 81 and 26) and without (n = 313 and 25) vascular complications from two cross-sectional Scandinavian cohorts (PROLONG and DIALONG) using Luminex technology. A subset of PROLONG individuals (n = 61) was screened for circulating immune cells using multicolor flow cytometry. We found that elevated plasma levels of soluble interleukin-2 receptor alpha (sIL-2R) were positively associated with the complication phenotype. Risk carriers of polymorphisms in the IL2RA and PTPN2 gene region had elevated plasma levels of sIL-2R. In addition, cell surface marker analysis revealed a shift from naïve to effector T cells in T1D individuals with vascular complications as compared to those without. In contrast, no difference between the groups was observed either in IL-2R cell surface expression or in regulatory T cell population size. In conclusion, our data indicates that IL2RA and PTPN2 gene variants might increase the risk of developing vascular complications in people with T1D, by affecting sIL-2R plasma levels and potentially lowering T cell responsiveness. Thus, elevated sIL-2R plasma levels may serve as a biomarker in monitoring the risk for developing diabetic complications and thereby improve patient care.

Liver nucleotide biosynthesis is linked to protection from vascular complications in individuals with long-term type 1 diabetes.

Identification of biomarkers associated with protection from developing diabetic complications is a prerequisite for an effective prevention and treatment. The aim of the present study was to identify clinical and plasma metabolite markers associated with freedom from vascular complications in people with very long duration of type 1 diabetes (T1D). Individuals with T1D, who despite having longer than 30 years of diabetes duration never developed major macro- or microvascular complications (non-progressors; NP) were compared with those who developed vascular complications within 25 years from diabetes onset (rapid progressors; RP) in the Scandinavian PROLONG (n = 385) and DIALONG (n = 71) cohorts. The DIALONG study also included 75 healthy controls. Plasma metabolites were measured using gas and/or liquid chromatography coupled to mass spectrometry. Lower hepatic fatty liver indices were significant common feature characterized NPs in both studies. Higher insulin sensitivity and residual ß-cell function (C-peptide) were also associated with NPs in PROLONG. Protection from diabetic complications was associated with lower levels of the glycolytic metabolite pyruvate and APOCIII in PROLONG, and with lower levels of thiamine monophosphate and erythritol, a cofactor and intermediate product in the pentose phosphate pathway as well as higher phenylalanine, glycine and serine in DIALONG. Furthermore, T1D individuals showed elevated levels of picolinic acid as compared to the healthy individuals. The present findings suggest a potential beneficial shunting of glycolytic substrates towards the pentose phosphate and one carbon metabolism pathways to promote nucleotide biosynthesis in the liver. These processes might be linked to higher insulin sensitivity and lower liver fat content, and might represent a mechanism for protection from vascular complications in individuals with long-term T1D.

Endothelin-A receptor blockade increases nutritive skin capillary circulation in patients with type 2 diabetes and microangiopathy.

AIMS: Endothelin-1 levels are elevated in patients with type 2 diabetes mellitus and may contribute to impaired microvascular function. We investigated the effect of selective endothelin-A (ET(A)) receptor blockade (BQ123) on skin microcirculation in patients with type 2 diabetes and albuminuria. METHODS: Ten type 2 diabetes patients and 8 non-diabetic controls were investigated. Nutritive skin capillary circulation, investigated by videophotometric capillaroscopy, and total skin microcirculation, assessed by laser Doppler flux-metry (LDF), were studied during intra-arterial infusion of saline for 15 min, followed by BQ123 infusion for 60 min. RESULTS: Following BQ123 infusion there was a significant increase in resting capillary blood cell velocity (CBV) in patients with type 2 diabetes from 0.24 (0.20-0.34) mm/s at baseline to 0.61 (0.46-0.88) mm/s at 60 min, but no significant change in the control subjects [0.55 (0.10-0.68) vs. 0.38 (0.13-0.88) mm/s; p < 0.005 for difference between groups]. Peak CBV following arterial occlusion and skin temperature increased significantly in the type 2 diabetes group but not in the control group during BQ123 infusion. There were no significant changes in LDF parameters during infusion of BQ123 in either group. CONCLUSION: ET(A) receptor blockade improves nutritive skin capillary circulation in patients with type 2 diabetes and microangiopathy.

Skin reactions induced by experimental exposure to setae from larvae of the northern pine processionary moth (Thaumetopoea pinivora).

BACKGROUND: Moth larvae that carry noxious hairs (setae) are spread worldwide. A population of the northern pine processionary moth (Thaumetopoea pinivora, TP) is present on the island of Gotland in the Baltic Sea. This study aimed to evaluate the local skin reactions following experimental exposure to TP setae. SUBJECTS AND METHODS: A drop of setae suspension was applied on the volar forearm of six volunteers. The local skin reactions were studied by microscopy and skin perfusion using laser Doppler (LD) scanning. RESULTS: Setae penetrated into the skin, and LD scanning showed marked increase in blood perfusion in all subjects. In two, with a history of severe symptoms, microscopic vacuoles developed around setae, followed by desquamation and severe symptoms. Remaining individuals, with only light symptoms during previous exposure, exhibited only mild reactions that disappeared within 3 weeks. In none of the volunteers, immunoglobulin (Ig) E or IgG4 antibodies to larval antigens were found. CONCLUSION: Experimental skin exposure to TP setae induces local inflammatory reactions independent of earlier exposure to TP. The degree of reaction correlated well with the magnitude of symptoms during natural exposure. The initial reaction mimics a 'foreign body reaction' that varies depending on individual predisposition.

Phosphatidylserine expressing microvesicles in relation to microvascular complications in type 1 diabetes.

INTRODUCTION: Type 1 diabetes is a prothrombotic state strongly linked to vascular complications. The role of microvesicles (MVs) as mediators and potential biomarkers in microangiopathy in type 1 diabetes remains unclear. MATERIALS AND METHODS: MV levels in plasma samples from 106 patients with type 1 diabetes with microangiopathy, 130 patients without microangiopathy and 100 healthy controls were analysed using flow cytometry. Phosphatidylserine (PS) expression in MVs was assessed by lactadherin, and the ability of MVs to induce thrombin generation was investigated in vitro. Endogenous plasma lactadherin levels were measured using ELISA. RESULTS: Patients with type 1 diabetes had higher MV levels compared to healthy controls, with no significant differences between patients with and without microangiopathy. MV-induced thrombin generation in normal-pooled plasma was blocked by addition of lactadherin. Endogenous lactadherin levels were higher in patients compared to controls, and the highest levels were found in patients with microangiopathy. Plasma lactadherin levels did not correlate with levels of PS positive/negative MVs. CONCLUSION: Patients with type 1 diabetes with and without microangiopathy have higher levels of circulating MVs than healthy controls, probably reflecting higher cellular activation and turnover. However, we found no associations between clinical microangiopathy and levels of MVs in total or PS-expressing MVs. Plasma levels of lactadherin, which is a glycoprotein important in the clearance of cells and MVs, are increased in patients with type 1 diabetes and correlate with microangiopathy.

Beneficial effects of dalteparin on haemostatic function and local tissue oxygenation in patients with diabetes, severe vascular disease and foot ulcers.

INTRODUCTION: A state of hypercoagulation and fibrinolytic dysfunction is present in individuals with diabetes, which may contribute to disturbed skin microcirculation and impaired ulcer healing. We have previously reported an improved outcome of chronic diabetic foot ulcers during treatment with dalteparin. In the present study we investigated the effects of dalteparin on skin microcirculation and haemostatic function. MATERIALS AND METHODS: 87 patients with diabetes, peripheral arterial obliterative disease and chronic foot ulcers were investigated in a prospective, randomised, double-blind and placebo-controlled study. They were randomised to treatment with subcutaneous injections of 5000 U dalteparin (n=44) or placebo (n=43), once daily until ulcer healing or for a maximum of six months. Plasma fibrinogen, fibrin gel structure [permeability coefficient (Ks) and fiber mass/length ratio (mu)], prothrombin fragment 1+2 (F1+2) antigen, plasminogen activator inhibitor-1 (PAI-1) activity and tissue plasminogen activator (tPA) antigen were analysed before randomization (baseline value), and at the end of the treatment period. The skin microcirculation of the foot was investigated by transcutaneous oxygen tension (TcPO(2)) and laser Doppler fluxmetry (LDF). RESULTS: The changes (Delta-values) of Ks, mu, tPA and TcPO(2) were higher (p<0.05) during treatment with dalteparin, as compared to the changes during treatment with placebo. At baseline, plasma fibrinogen and Ks were significantly correlated to TcPO(2). CONCLUSIONS: Local skin oxygenation improved and a less thrombogenic fibrin gel structure was formed in patients treated with dalteparin. Beneficial effects on haemostatic function are likely to contribute to the improved skin oxygenation observed during treatment with dalteparin.