Large platelets circulate in an activated state in diabetes mellitus

Diabetes mellitus is associated with aggravated development of vascular complications. Yet, it has not been established whether platelet hyperreactivity contributes as a pathogenetic factor. In order to study the role of activated platelets in diabetes mellitus, we investigated the expression of the membrane activation markers CD63 (GP53) and CD62 (GMP-140) as direct indicators of in vivo activation. The CD63-positive fraction was significantly higher in patients (6.1% X 3.7 +/- 1) than in controls (2.7% X 3 +/- 1). In parallel, the CD62-positive fraction was significantly elevated in patients to 5% X 2.5 +/- 1 in comparison to controls (3% X 2 +/- 1). Patients with angiopathy had a mean increase of 304% in CD63-positive and of 223% in CD62-positive platelets. Patients without clinically detectable angiopathy showed a trend to an increased fraction in CD63-/CD62-positive platelets. There was no correlation of the activation markers with fasting blood glucose, HbA1 or platelet count. CD63 platelet bound fluorescence significantly increased with platelet size in the patient group. We conclude that in diabetes mellitus an increased number of large platelets circulate in an activated state predominantly in patients with angiopathy. This could imply that platelets become activated by vascular lesions. The trend in patients without vascular disease, however, suggests that activated platelets may also basically contribute to the prethrombotic state in diabetes mellitus.

Evidence for abnormal platelet glycoprotein expression in diabetes mellitus

In 41 diabetics (27 type I, 14 type II) and in 23 healthy controls the number of glycoprotein (GP) GPIB and GPIIB/IIIA molecules were determined on resting, peripheral platelets by means of flowcytometry after immunostaining with monoclonal antibodies which bind independently from the state of activation. The average number of both glycoproteins per platelet was significantly elevated (GPIB: 54,100 x 1.27 +/- 1 vs. 39,100 x 1.3 +/- 1 GPIIB/IIIA: 77,500 x 1.3 +/- 1 vs. 62,700 x 1.3 +/- 1, in diabetic patients. Platelet volume was significantly correlated with the number of GPIB molecules on normal and diabetic platelets (r (normal) = 0.52 +/- 0.07; r (diabetic) = 0.46 +/- 0.1). Additionally, von Willebrand factor-related antigen (vWF: AG) was increased to 129% x 1.3 +/- 1 in diabetics vs. 111% x 1.4 in controls. The increase of vWF: AG was significantly correlated with HbA1 (r = 0.38*) and seemed to depend on chronic hyperglycaemia. Since platelet glycoprotein receptor status is regulated by the bone-marrow megakaryocyto- thrombopoiesis, our observations support the hypothesis that platelet hyperactivity in the diabetic state may be due to primarily altered production of platelets with an increased number of functional glycoproteins. This may be paralleled by increased plasma levels of cytoadhesive proteins like vWF: AG, which interact with the studied glycoproteins and thereby potentiate the risk of disturbed microhaemorrheology.

Platelet membrane activation markers are predictive for increased risk of acute ischemic events after PTCA

BACKGROUND

We wished to investigate whether platelet activation is related to the clinical outcome during the 24 hours immediately after elective percutaneous transluminal coronary angioplasty (PTCA).

METHODS AND RESULTS

In 102 patients with high-grade coronary stenosis admitted for elective PTCA, preprocedural platelet activation was characterized by flow cytometric measurement of the proteins CD62, CD63, and thrombospondin expressed on the platelet surface membrane. The prevalence of acute ischemic events during the 24 hours immediately after the procedure was then related to the pre-PTCA platelet activation status. Fifty-six patients were classified as "nonactivated," whereas 46 patients showed an increased percentage of activated platelets. Two patients developed acute occlusion (1.96%) and four patients high-grade restenosis (3.92%), as confirmed by second-look coronary angiography. All events occurred in patients classified as "activated" (six of 46, or 13%). None of these patients received beta-blocker medication, which was associated with lower expression of platelet membrane activation markers. In the nonactivated patient group, no clinical events were found (0 of 56, or 0%). This difference in prevalence is significant (p = 0.007).

CONCLUSIONS

We conclude that analysis of platelet membrane activation markers may help to predict an increased risk of acute ischemic events after angioplasty.

Autologous stem cell therapy in the treatment of limb ischaemia induced chronic tissue ulcers of diabetic foot patients

BACKGROUND AND AIM

Despite improvements in surgical revascularisation, limitations like anatomical factors or atherosclerosis limit the success of revascularisation in diabetic patients with critical limb ischaemia. Stem cells were shown to improve microcirculation in published studies. The aim of this study was to evaluate safety, feasibility and efficacy of transplantation of bone marrow derived cellular products regarding improvement in microcirculation and lowering of amputation rate.

METHODS

Bone marrow mononuclear cells (BMCs) in comparison with expanded bone marrow cells enriched in CD90+ cells ('tissue repair cells', TRCs) were used in the treatment of diabetic ulcers to induce revascularisation. Diabetic foot patients with critical limb ischaemia without option for surgical or interventional revascularisation were eligible. Parameters examined were ABI, TcPO(2) , reactive hyperaemia and angiographic imaging before and after therapy.

RESULTS

Of 30 patients included in this trial, 24 were randomised to receive either BMCs or TRCs. The high number of drop-outs in the control group (4 of 6) led to exclusion from evaluation. A total of 22 patients entered treatment; one patient in the TRC group and two in the BMC group did not show wound healing during follow up, one patient in each treatment group died before reaching the end of the study; one after having achieved wound healing (BMC group), the other one without having achieved wound healing (TRC group). Thus, 18 patients showed wound healing after 45 weeks. The total number of applicated cells was 3.8 times lower in the TRC group, but TRC patients received significantly higher amounts of CD90+ cells. Improvement in microvascularisation was detected in some, but not all patients by angiography, TcPO(2) improved significantly compared with baseline in both therapy groups.

CONCLUSION

The transplantation of BMCs as well as TRCs proved to be safe and feasible. Improvements of microcirculation and complete wound healing were observed in the transplant groups.

Platelets in diabetes: the role in the hemostatic regulation in atherosclerosis

Vascular diseases and related complications still represent the main cause of death in diabetic patients. Neuropathy, nephropathy, retinopathy, and disturbed nutritive tissue perfusion may result from reduced capillary microcirculation. These disturbances are diabetes specific. Macroangiopathy does not differ structurally from atherosclerotic lesions of nondiabetic subjects, but leads to accelerated cerebral, coronary, and peripheral artery disease. Occurrence of life-terminating thrombotic events, which are superimposed on those vascular lesions, are increased. Thus, morbidity and mortality of diabetics depend mainly on vascular complications. Normal blood flow is a prerequisite of adequate organ perfusion and results from vasomotion, plasma components, corpuscular blood elements, vascular architecture, and the undisturbed interaction of these components at the endothelial interface. Functional thromboresistance of the endothelial layer is reduced in the diabetic state. Increased intravascular thrombin generation, reduced fibrinolytic potential, and hyperactive platelets lead to a prethrombotic state. This thrombotic diathesis increases the permanent danger of acute flow interruption. Activated platelets operate by three mechanisms: (1) Microembolization of the capillaries; (2) local progression of preexisting vascular lesions by secretion of constrictive, mitogenic, and oxidative substances; (3) trigger of the prognosis-limiting arterial thrombotic event. We were able to show that the increased functional properties of diabetic platelets result from the primary release of larger platelets with enhanced thromboxane formation capacity and increased numbers of functional glycoprotein receptors GPIb and GPIIb/IIIa, which are synthesized in the megakaryocytes. The megakaryocyte-platelet system is turned on in diabetes mellitus. It could be demonstrated with the Duesseldorf III method of flow cytometric activation marker testing (CD62, CD63, thrombospondin) that predominantly large platelets circulate in an activated state in diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet-leukocyte-cross-talk in diabetes mellitus

The physiological meaning of platelets has been best documented for acute coronary syndromes where platelets act as "first responsive elements" triggering the final occlusive thrombus after plaque rupture has occurred. This situation is particularly relevant for patients with NIDDM-type diabetes regularly showing complicated plaque architecture. Predictive power for acute ischemic events e.g. following angioplasty has been proven, and this has dominated the attention exclusively towards the hemostatic function of platelets. Meanwhile, a variety of particularly important platelet features have been identified: a) promotion of liquid phase coagulation; b) regulation of the local vascular tone; c) active modulation of tissue modeling at lesion sites; d) adhesion molecule-mediated communication with a variety of corpuscular blood (and non-blood cells). With emerging recognition of the latter role, the pathophysiological scope of platelets exceeds the well-established role as microemboli, local atherosclerosis amplifiers and triggers of gross thrombosis. In diabetes mellitus of either type, increased populations of circulating platelets have been identified expressing activation dependent adhesion molecules such as activated alpha 2 beta 3 (GPIIbIIIa), lysosomal GP53, thrombospondin or, perhaps most importantly "P-selectin" (CD62 p). This suggests that these adhesion molecules among others can also mediate platelet-leukocyte interactions potentially resulting in inflammatory tissue damaging processes in addition to the immanent tendency towards (micro-)thrombosis. This review works out a more general view on the meaning of platelet activation beyond hemostaseology and updates the actual knowledge of platelet-leukocyte communication checkpoints with particular reference to the diabetic state outlining new pharmacological concepts for intervention.

Flow-cytometric detection of surface membrane alterations and concomitant changes in the cytoskeletal actin status of activated platelets

Occlusive vascular diseases are promoted by a "prethrombotic state" with increased platelet activity. Polymerization of cytoskeletal proteins and exposure of subcellular structures or rebinding of secreted proteins have been characterized as early reactions after platelet activation preceding adhesion and aggregation. Here, we demonstrate the kinetic increase in specific binding of monoclonal antibodies to thrombospondin (P10) and to platelet membrane activation markers CD63 (GP53, a 53 kD lysosomal protein) and CD62 (GMP140, a 140 kD alpha granule protein) by using a flow-cytometric bio-assay and the related change in the actin status by using the DNase-I inhibition assay after stimulation of normal human platelets with 0.2 U/ml thrombin. F-actin was raised from 41% to 51% of total platelet actin content 30 s after stimulation and remained thereafter constant (50% at 60 s). Simultaneously, the percentage of P10, CD63, and CD62 positive platelets was elevated from 5.4%, 24.4%, and 9.1% to 67.4%, 80.2%, and 82.3% respectively. The mean number of P10, CD63, and CD62 antibody binding sites increased from 3,300, 1,715, and 2,146 to 6,400, 6,800, and 9,016 per platelet. Conclusively, changes in the organization of the cytoskeletal protein "actin" and exposure of subcellular structures indicating platelet secretion can be regarded as markers of early platelet activation. Thus, the parallel response in both analytical systems provides further support for the diagnostic concept of flow-cytometric detection of preactivated platelets in the peripheral blood by using fluochrome staining procedures detecting activation dependent structural alterations directly at the cellular level.

Exposure of adhesion molecules on activated platelets in patients with newly diagnosed IDDM is not normalized by near-normoglycemia

It has been suggested that platelet hyperactivity contributes to the early evolution of diabetic vascular disease per se. This study directly evaluates the level of intravascular platelet activation in newly diagnosed IDDM patients before and after tight metabolic control. Platelet activation was determined by the Duesseldorf-III flow cytometry assay in 21 recent-onset hyperglycemic IDDM patients before insulin, after 3 days of treatment with intravenous insulin, and after 14 and 60 days of intensified conventional insulin therapy. The intravasal platelet activation status was quantified by the percentage of platelets exposing the activation-dependent molecules CD62 (P-selectin), thrombospondin (TSP), and CD63 (GP53) as well as the activated fibrinogen receptor (GPIIB/IIIA). Fifty matched normal subjects served as control subjects. Fourteen patients completed the 60-day study design. After initial recompensation, near-normoglycemic control was achieved after 14 days (fasting blood glucose, 117.0 +/- 19.0 mg/dl), and the HbA1 concentration was 7.6 +/- 1.2% after 60 days. CD62+ (4.0 +/- 4.5%), TSP+ (2.0 +/- 1.8%), CD63+ (11.0 +/- 7.0%), and activated-GPIIB/IIIA+ (7.6 +/- 7.7%) platelet levels were initially 5, 3.3, 5.7, and 2.8 times higher than the mean level of normal. There was no correlation with any of the nearly normalized metabolic parameters. Thus, more activated platelets circulate in newly diagnosed IDDM patients, which supports the assumption of a prethrombotic condition even in disease stages without apparent vascular damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral glucose tolerance test and HbA₁c for diagnosis of diabetes in patients undergoing coronary angiography: [corrected] the Silent Diabetes Study

AIMS/HYPOTHESIS

The primary aim of this study was to compare the results of HbA(1c) measurements with those of an OGTT for early diagnosis of 'silent diabetes' in patients with coronary artery disease (CAD) undergoing angiography without prediagnosed diabetes. A secondary aim was to investigate the correlation between the extent of CAD and the glycaemic status of the patient.

METHODS

Data from 1,015 patients admitted for acute (n = 149) or elective (n = 866) coronary angiography were analysed. Patients with known diabetes were excluded from the study. Using the OGTT results, patients were classified as having normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes. According to the results of the HbA(1c) measurements, patients were classified into three groups: normal (HbA(1c) <5.7% [<39 mmol/mol]), borderline (HbA(1c) 5.7-6.4% [39-47 mmol/mol]) and diabetes (HbA(1c) ≥6.5% [≥48 mmol/mol]).

RESULTS

Based on the OGTT, 513 patients (51%) were classified with NGT, 10 (1%) with IFG, 349 (34%) with IGT and 149 (14%) were diagnosed with diabetes. According to HbA(1c) measurements, 588 patients (58%) were classified as normal, 385 (38%) as borderline and 42 (4%) were diagnosed with diabetes. The proportion of patients with IGT and diabetes increased with the extent of CAD (IGT ρ = 0.14, p < 0.001, diabetes ρ = 0.09, p = 0.01). No differences in HbA(1c) were seen among the groups with different extents of CAD (p = 0.652).

CONCLUSIONS/INTERPRETATION

An OGTT should be performed routinely for diagnosis of diabetes in patients with CAD undergoing coronary angiography, since HbA(1c) measurement alone appears to miss a substantial proportion of patients with silent diabetes. A limitation of the study is that the OGTT was not performed before the angiography.

Activated platelets in subjects at increased risk of IDDM. DENIS Study Group. Deutsche Nikotinamid Interventionsstudie

Activated platelets respond to activated leukocytes and endothelial cells via adhesion molecules linking inflammation and thrombosis. Platelets of recent-onset insulin-dependent diabetic (IDDM) patients have been shown to be activated independent of metabolic control. This study evaluates the levels of circulating activated platelets exposing adhesion molecules in healthy subjects at increased risk of IDDM (surface markers were: P-selectin (CD62), thrombospondin, lysosomal GP53 (CD63). From the DENIS and the ENDIT screening programmes 19 identified islet cell antibody positive (titre > or = 20 Juvenile Diabetes Foundation units) first degree relatives of IDDM patients (male/female 9/10; age 22 +/- 15 years; body mass index (BMI): 20.0 +/- 4.3 kg/m2) with clearly normal metabolism (HbA1: 6.1 +/- 0.8%; fasting blood glucose: 4.95 +/- 0.67 mmol/l) were available for this investigation. Platelet CD62 as well as thrombospondin and CD63 expression were determined by flow cytometry. We matched 50 normal volunteers for age (29 +/- 6 years), anthropometric measures (male/female 26/24; BMI: 22.3 +/- 2.8 kg/m2) and metabolic parameters (HbA1: 5.8% +/- 0.3; fasting blood glucose: 4.41 +/- 0.53 mmol/1) served as control subjects. The mean number of CD62+ platelets was increased 3.2-times in prediabetic patients: 1.94 x 2.91 (+/- 1) vs 0.60 x 1.83 (+/- 1%), p < 0.0001. Thrombospondin+ and CD63+ platelet levels were concomitantly increased (1.45 x 2.38( +/- 1)/5.97 x 2.89 (+/- 1)% vs 0.52 x 2.01 (+/-1)/1.64 x 2.26 (+/-1)%, p < 0.0001 for both comparisons). Thus, intravasal platelet activation is already present in potentially prediabetic subjects representing an antecedent, potentially pathogenic feature of IDDM.

Large platelets continue to circulate in an activated state after myocardial infarction

This study was intended to investigate the actual platelet activation status after an acute coronary event. The activation status of circulating platelets was assayed directly by measuring the membrane activation markers CD62 and CD63 with the Düsseldorf III flow cytometry test in 22 patients with the diagnosis of acute myocardial infarction during the 48-h observation period following the acute event. The number of activated, marker-positive sample platelets was significantly increased in the post-MI patients: CD62: 5.8% x 2.25 +/- 1 vs. 3.5% x 2.32 +/- 1, P < or = 0.05; CD63: J8.7% x 1.77 +/- 1 vs. 4.6% x 2.16 +/- 1, P < or = 0.00.1. The platelet volume and count were concomitantly increased (12.1 +/- 2.4 fl/ 236 +/- 90 x 10(3) microliters-1 compared to 8.3 +/- 1.6 fl/ 187 +/- 42 x 10(3) microliters-1) in the control group. Particularly large platelets were identified as being activated documented by the exponential increase in the difference in CD63-binding sites per sample platelet above the 90%-percentile and below the 10%-percentile of the volume distribution: delta + 1341 +/- 903 (MI patients) vs. delta + 276 +/- 126 (controls), P < or = 0.00.1. Significant creatine kinase elevation and decrease in platelet count was found in the non-survivor subset (n = 5). We conclude that predominantly large platelets continue to circulate in an activated state after MI. This study provides direct evidence that the assumption of an increased thrombotic potential becomes operative in vivo in MI patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The activated megakaryocyte-platelet-system in vascular disease: focus on diabetes

Vascular diseases and related complications still represent the main cause of death. In diabetes neuropathy, nephropathy, retinopathy and disturbed nutritive tissue perfusion result from reduced capillary microcirculation. These disturbances are diabetes specific, whereas macroangiopathy does not differ structurally from atherosclerotic lesions of non-diabetic subjects, but leads to accelerated cerebral, coronary and peripheral artery disease. Occurrence of life terminating thrombotic events which are superimposed to those vascular lesions is increased. Thus, morbidity and mortality of diabetes depend mainly on vascular complications. Normal blood flow is a prerequisite of adequate organ perfusion and results from vasomotion, plasma components, corpuscular blood elements, vascular architecture and the undisturbed interaction of these components at the endothelial interface. Functional thromboresistance of the endothelial layer is reduced in the diabetic state. Increased intravascular thrombin generation, reduced fibrinolytic potential and hyperactive platelets lead to a prethrombotic state. This thrombotic diathesis raises the permanent danger of acute flow disruption. Activated platelets operate by three mechanisms: 1. microembolization of the capillaries; 2. local progression of preexisting vascular lesions by secretion of constrictive, mitogenic, and oxidative substances; and 3. trigger of the prognosis limiting arterial thrombotic event. We were able to show that the increased functional properties of diabetic platelets result from the primary release of larger platelets with enhanced thromboxane formation capacity and increased numbers of functional glycoprotein receptors GPIB and GPIIB/IIIA which are synthesized in the megakaryocytes. The megakaryocyte-platelet system is turned on in diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

PTCA: periprocedural platelet activation. Part II of the Duesseldorf PTCA platelet study (DPPS)

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) with its various manipulations could create a dangerous, sudden haemostatic response. This study was performed to investigate PTCA-induced periprocedural changes in platelet activation and its consequences.

METHODS

Twenty-five consecutive patients admitted for elective PTCA were preclassified as having or not having circulating activated platelets. Blood samples were taken for platelet activation marker analysis before, six times during and 2 h after PTCA. Intravascular platelet activation was analysed by flow cytometry to measure activation-dependent surface markers thrombospondin, P-selectin (CD62) and lysosomal GP53 (CD63).

RESULTS

PTCA was associated with a significant reduction of peripheral platelet count. The initiation of the PTCA procedure led to a significant loss of more than 50% of the degranulated, activated platelets. After PTCA, the number of degranulated, activated platelets uniformly increased.

CONCLUSIONS

We conclude that PTCA can induce consumption, particularly of preactivated platelets, and lead to sustained platelet activation after the procedure. This might explain why preactivated patients are at increased risk of suffering periprocedural ischaemic events and why increased thrombogenicity favours acute flow disruption and the progression of coronary stenosis at the lesion site.

Wound therapy with autologous bone marrow stem cells in diabetic patients with ischaemia-induced tissue ulcers affecting the lower limbs

Previous studies suggest that autologous transplantation of bone marrow mononuclear cells is safe and effective in inducing therapeutic angiogenesis in patients with peripheral arterial occlusive disease (PAOD). Here we discuss a multidisciplinary approach to treating PAOD with a focus on the use of angiological diagnostic tools. We conclude that our autologous stem cell therapy is working in this patient and it is a potential new therapeutic option for diabetic patients with chronic foot ulcers induced by critical limb ischaemia.

Platelet activation in diabetic cardiovascular autonomic neuropathy

AIMS

Platelet activation is known to be associated with arrhythmic effects in myocardial ischaemia. The present study attempts to clarify whether diabetic cardiovascular autonomic neuropathy (CAN) is associated with intravascular platelet activation.

METHODS

Platelet activation was assessed by flow cytometry analysis in 30 patients with Type 1 diabetes mellitus screened for diabetic complications. Fifteen patients showed evidence of CAN as assessed by a battery of standard cardiovascular autonomic reflex tests. Fifteen patients without CAN were then selected as a matched control group. Platelet activation was assessed by flow cytometric detection of activation-dependent platelet membrane antigens (P-selectin (CD62), thrombospondin, lysosomal GP53 (CD63) and ligand-induced binding site-1 of GPIIb/IIIa (LIBS-1)).

RESULTS

Significantly more activated platelets were detected in the patients with CAN showing 20.9% (coefficient of variation (CV) 44%) CD63+ (vs. 17.2% (CV 19%) in controls, P < or = 0.05), 6.4% (CV 87%) CD62+ (vs. 4.1% (CV 37%), P < or = 0.05), and 6.7% (CV 55%) thrombospondin+ (vs. 4.6% (CV 39%), P < or = 0.01) platelets, respectively. LIBS-1 on platelets was not significantly different between patients with and without CAN. No correlation was found between glucose metabolism and platelet activation.

CONCLUSIONS

Cardiovascular autonomic neuropathy is associated with platelet activation in Type 1 diabetes mellitus. The high platelet activation may reflect an increased prothrombotic state in diabetic cardiovascular autonomic dysfunction.

Heat shock protein 27 modification is increased in the human diabetic failing heart

Chronic conditions like diabetes mellitus (DM) leading to altered metabolism might cause cardiac dysfunction. Hyperglycemia plays an important role in the pathogenesis of diabetic complications including accumulation of methylglyoxal (MG), a highly reactive alpha-dicarbonyl metabolite of glucose degradation pathways and increased generation of advanced glycation endproducts (AGEs). The aim of this investigation was to study the extent of the MG-modification argpyrimidine in human diabetic heart and in rat cardiomyoblasts grown under hyperglycemic conditions. Left ventricular myocardial samples from explanted hearts of patients with cardiomyopathy with (n=8) or without DM (n=8) as well as nonfailing donor organs (n=6), and rat cardiac myoblasts H9c2 treated with glucose were screened for the MG-modification argpyrimidine. The small heat shock protein 27 (Hsp27) revealed to be the major argpyrimidine containing protein in cardiac tissue. Additionally, the modification of arginine leading to argpyrimidine and the phosphorylation of Hsp27 are increased in the myocardium of patients with DM. In H9c2 cells hyperglycemia leads to a decrease of the Hsp27-expression and an increase in argpyrimidine content and phosphorylation of Hsp27, which was accompanied by the induction of oxidative stress and apoptosis. This study shows an association between diabetes and increased argpyrimidine-modification of myocardial Hsp27, a protein which is involved in apoptosis, oxidative stress, and cytoskeleton stabilization.

Response of human monocyte-derived dendritic cells to immunostimulatory DNA

Activated dendritic cells (DC) are of key importance for the initiation of primary immune responses and represent promising tools for immunotherapies in humans. Since DNA containing CpG motifs have been described as potent immunostimulatory (IS) adjuvants for murine DC, we here studied maturation and stimulation of functional activity in human monocyte-derived DC (MODC) in response to several immunostimulatory oligodeoxynucleotides (IS-ODN) and plasmid DNA (IS-PL). We show that exposure of MODC to IS-PL, but not IS-ODN, induced a dose-dependent strong up-regulation of HLA class II and co-stimulatory molecules (CD80, CD86), similar to that observed after treatment with TNF-alpha. Functional activity was assessed by the detection of increased secretions of IL-6 and IL-12(p75) following treatment with IS-PL. In addition, IS-PL-stimulated MODC acquired a high T cell-stimulatory capacity. T cells stimulated by tetanus toxoid-pulsed, IS-PL-matured MODC were significantly more frequently IFN-gamma positive (25.2+/-2.7%) as compared to TNF-alpha-treated MODC (15.4+/-1.4%), indicating a strong activation of Th1 lymphocytes. In conclusion, we demonstrate that human MODC are activated by IS-PL but not IS-ODN previously used as adjuvants in animal models. The Th1-like immune response observed after stimulation with IS-PL-treated DC suggests that preincubation of human MODC with IS-PL or coimmunization with IS-PL may represent an useful approach to generate strongly activated human MODC for several therapeutic applications such as DC-based tumor immunotherapy.

Angina intensity is not different in diabetic and non-diabetic patients with acute myocardial infarction

BACKGROUND

Diabetic patients with acute myocardial infarction (AMI) may have diminished pain or a higher frequency of asymptomatic infarctions. This appears to be a common clinical perception.

METHODS

Data from two registries of AMI patients presenting in hospital (MITRA PLUS with 18786 patients; North German Registry, NGR, 1042 patients with detailed symptom interviews) were analyzed concerning symptoms of acute myocardial infarction in patients with diabetes mellitus (DM) and without diabetes (non-DM).

RESULTS

DM patients were significantly older and more often female than non-DM. There were no differences in the frequency of pre-infarction angina between DM and non-DM (Mitra Plus). In NGR, severe angina during AMI occurred in 49.8% of DM and 46.3% of non-DM (n. s.). No chest pain was reported in 16.9% of DM and 15.0% of non-DM (n. s.). Extra-thoracic pain, dizziness, nausea, sweating, palpitations, radiation of angina and localization of radiating pain was not different between DM and non-DM patients. Severe dyspnea occurred in 29.5% of DM and 19.5% of non-DM patients (p = 0.003).

CONCLUSIONS

Apart from a higher frequency of severe dyspnea in diabetics, there appears to be no difference in the clinical symptoms of AMI patients with and without diabetes mellitus. AMI with little or no angina was also frequently found in non-diabetics. In the hospital, diabetics with suspected AMI do not appear to need a special judgement of symptoms. This could accelerate access of diabetics to standard therapeutic procedures.

Beneficial Metabolic Effects of Duodenal Jejunal Bypass Liner for the Treatment of Adipose Patients with Type 2 Diabetes Mellitus: Analysis of Responders and Non-Responders

Implantation of a duodenal-jejunal endoluminal bypass liner (DJBL) has shown to induce weight loss and to improve metabolic parameters. DJBL is a reversible endoduodenal sleeve mimicking duodenal bypass while lacking risks and limitations of bariatric surgery.Effects on metabolic control, body mass parameters, appetite regulation, glucose tolerance, organ health, and lipid profile were determined in 16 morbidly overweight patients with type 2 diabetes mellitus. In addition, relevant hormones (leptin, ghrelin, gastric inhibitory peptide, glucagon-like peptide, and insulin) were measured by enzyme-linked immunosorbent assay (ELISA) and chemiluminescent microparticle immunoassay (CMIA) at 0, 1, 32, and 52 weeks post-implant following a mixed meal tolerance test. Lipoprotein subclasses were analysed by proton nuclear magnetic resonance (¹H NMR) spectrometry. DJBL provoked weight loss, a decrease in fat mass, and an improvement in insulin resistance and hepatic function in most but not all of the patients, but in the long term did not increase gut hormone fasting levels pointing to a combined effect of more than gut parameters alone. Lipidome analysis was done in 10 patients, allowing classification to responders and non-responders by reduction of sLDL-p subfraction; and to further analyse the atherogenic profile. Responders showed an overall more pronounced effect regarding improvement of HbA1c, BMI, and HOMA index.Implantation of a DJBL in obese type 2 diabetes patients does not per se lead to an improvement of the metabolic situation. Further analyses including larger cohorts have to be performed to identify responding patients, to better treat non-responders and to analyse the key effectors.

Leptin decreases postprandially in people with type 2 diabetes, an effect reduced by the cooking method

Leptin modulates satiety and increases in obesity and type 2 diabetes mellitus in parallel with leptin resistance. Postprandial leptin regulation has been previously postulated to depend on meal composition, but data are controversial. The hypothesis of our study was that in people with type 2 diabetes mellitus, a postprandial leptin regulation exists that can be regulated not only by meal composition but also by the cooking method. In 20 inpatients with type 2 diabetes (mean age: 55.9 years), the acute effects of 2 meals, a high-heat-processed meal HHPM or a low-heat-processed meal LHPM, on leptin levels were studied on 2 different days in a randomized, crossover design. Both test meals had similar ingredients and differed only in the cooking method used. Parameters were measured after an overnight fast and at 2, 4, and 6 h postprandially. The HHPM induced a marked decrease in leptin levels, from 8 717+/-2 079 pg/ml at baseline to 6 788+/-1 598 pg/ml at 2 h postprandially (-1 929 pg/ml, -22%*), an effect significantly reduced by the LHPM, where values were 8 563+/-1 900 pg/ml at baseline and 7 425+/-1 591 pg/ml at 2 h postprandially (-1 138 pg/ml, -13%* (double dagger)) (*p<0.05 vs. baseline, (double dagger)p<0.05 vs. HHPM). Parameters of oxidative stress and blood AGEs increased only following the HHPM, while postprandial glucose, triglycerides, and insulin excursions were similar between meals. Postprandial leptin decreases following a HHPM meal in people with T2DM, an effect reduced by the cooking method.

Genetic variation of the platelet- surface integrin GPIIb-IIIa (PIA1/A2-SNP) shows a high association with Type 2 diabetes mellitus

AIMS/HYPOTHESIS

The gene encoding the beta(3)-subunit (GPIIIa) of the platelet alpha(2)beta(3)-integrin (fibrinogen receptor) shows a polymorphism PlA1/A2 with the A2 allele putatively associated with an increased risk of acute ischaemic events. This study investigated whether Type 2 diabetes as a particular macrovascular risk factor associates with the thrombogenic PIA2 genotype.

METHODS

The PlA genotype was determined in 112 consecutive Type 2 diabetic patients additionally classified according to the presence of macrovascular disease. Forty-four non-diabetic patients with angiografically documented cardiovascular disease (CAD/ AMI) and a further 59 non-diabetic subjects with no angiografical signs of CAD were investigated as genomic background control (n=103). PIA-genotyping was carried out by standard restriction fragment length analysis (RFLA) of PCR amplified lymphocyte template DNA.

RESULTS

The overall allelic PlA2- prevalence accounted to 34.8% (39/112) in diabetic patients as compared to 14.6% (15/103) in non-diabetic patients [OR 3.1 (1.6-6.1), p<0.01]. This odds ratio increased to 7.0 (2.5-19.7), (p<0.01) in subjects free of criteria of macrovascular disease. In non-diabetic control subjects without CAD there was an allelic PIA2 frequency of 10.2% (6/59) as compared to 20.5% (9/44) in patients with CAD and a history of AMI being less than either diabetes subgroup. The PIA2 prevalence in the subgroup of diabetes patients with macrovascular complications did not differ from the respective value in patients without macrovascular disease. [29.0% (20/69) vs. 44.2% (19/43)].

CONCLUSION/INTERPRETATION

This study confirms a trendwise association of PlA2 with severe coronary artery disease, but rather suggests an even stronger, highly significant association with the metabolic condition of Type 2 diabetes mellitus. This justifies the speculation that pathways dependent on the platelet alpha(2)beta(3) integrin physiology could be implicated in the pathogenesis of Type 2 diabetes which lends further support to the "common soil" hypothesis of diabetes and vascular disease.

Leukocyte apoptosis in whole blood involves platelet-dependent coaggregation

BACKGROUND

Activated leukocytes and platelet-leukocyte interaction are involved in the pathogenesis of thrombotic and inflammatory events. Because apoptosis is a prerequisite for the successful resolution of an inflammatory response, we investigated the amount of apoptotic peripheral blood leukocytes (PBLs) in whole blood and their possible functional relation with the platelet-leukocyte interaction by a flow cytometric assay using APO 2.7 antibody for the detection of apoptosis

METHODS

Thirty healthy subjects volunteered for the study. PBL apoptosis in seven volunteers was induced by phorbol 12-myristate 13-acetate or while standing at rest.

RESULTS

Apoptosis was observed in all types of leukocytes (0.7% neutrophils, 1.5% monocytes, and 0.3% lymphocytes). Apoptosis was found predominantly in platelet and leukocyte coaggregates (<1% of nonaggregated leukocytes vs. 9% of platelet and leukocyte coaggregates). This phenomenon was even more pronounced after induction of leukocyte apoptosis in vitro (66% of platelet and leukocyte coaggregates).

CONCLUSIONS

Apoptosis and platelet-leukocyte interaction seemed to be closely related phenomena, and apoptotic leukocytes seemed to trigger adhesion and, hence, activation of platelets. Because platelet-leukocyte interaction is involved in the pathogenesis of thrombotic events, apoptotic leukocytes may constitute an additional prothrombotic trigger.

Heart disease in diabetes mellitus: a challenge for early diagnosis and intervention

Most people with diabetes die from thrombotic complications superimposed to degenerative arterial vascular lesions, mostly myocardial infarction. Diabetes is a risk factor per se for such complications, but often clusters with dyslipoproteinemia, hypertension and obesity. In NIDDM (Type-II) patients this is referred to as "metabolic syndrome" and often operates on a genetically programmed susceptibility which accelerates the pathogenesis of coronary artery disease in front of a much wider diabetes specific cardiopathy. From a pathophysiological point of view none of these associated risk factors explains the pathogenetic series of events leading to the precipitation of an occlusive thrombus at sites of complicated coronary plaques. In patients with diabetes the coagulation system is switched towards a prethrombotic state, involving increased plasmatic coagulation, diminished fibrinolysis, decreased endothelial thromboresistance and predominantly platelet hyperreactivity ("diabetic thrombocytopathy"). Some of these factors are associated with an increased coronary risk (e.g. fibrinogen, PAI-1, platelets), but are also directly linked to the pathogenesis of "atherothrombosis". Altered cardiac remodelling together with adhesion and coagulation mechanisms appears suitable to explain decreased functional performance of infarcted organs, decreased success of acute (reduced fibrinolytic response, reperfusion injury) and longterm intervention strategies (PTCA, CABG) in diabetes. Glucose adjustment alone will not adequately neutralize these complex mechanisms. Particularly in diabetes a multidimensional interventional repertoire is required including antihypertensive, antidyslipoproteinemic and antithrombotic drugs, customized according to the individual patients needs as assessed by early diagnostic measures ("early secondary prevention").