Seitarou Omoto

Significance of chemokines and activated platelets in patients with diabetes

Levels of platelet‐derived microparticles (PMPs), platelet activation markers (P‐selectin expressed on, or annexin V binding to, platelets (plt:P‐selectin or plt:annexin V, respectively)), chemokines (IL‐8, monocyte chemotactic peptide‐1 (MCP‐1), and regulated on activation normally T‐cell expressed and secreted (RANTES)), and soluble P‐ and E‐selectins were compared in peripheral blood from diabetic and control patients in order to develop a better understanding of their potential contribution to diabetic vascular complications. Significant increases were found for PMPs, plt:P‐selectin, MCP‐1, RANTES and soluble P‐ and E‐selectins in diabetic individuals, whereas IL‐8 levels were similar. Furthermore, after ticlopidine treatment, most of these factors receded to baseline levels observed in non‐diabetic patients. Our findings indicate that ticlopidine might be able to prevent or reduce vascular complications in diabetic patients.

Detection of monocyte-derived microparticles in patients with Type II diabetes mellitus

Aims/hypothesis. The role of plasma monocyte-derived microparticles (MDMPs) and platelet-activation markers (platelet-derived microparticle [PDMP], platelet-bound CD62P [plt-CD62P], and platelet-bound CD63 [plt-CD63]) in diabetic vascular complications is not clear. We measured and compared plasma concentrations of MDMPs and the platelet-activation markers to investigate their possible contribution to diabetic vascular complications. Methods. Activated platelets and microparticles (PDMP and MDMP) were analysed by flow cytometry. Concentrations of serum sE-selectin were measured with enzyme-linked immunosorbent assay. Results. The concentration of MDMPs in diabetic patients was higher than in normal subjects. We found no differences in the binding of anti-GPIIb/IIIa and anti-GPIb monoclonal antibodies between groups. There were differences, however, in the concentrations of PDMPs, plt-CD62P, and plt-CD63 between Type II (non-insulin-dependent) diabetes mellitus patients and control subjects (PDMPs: 585 ± 25 vs 263 ± 9, p < 0.01; plt-CD62P: 28.1 % ± 1.4 % vs 9.4 % ± 0.6 %, p < 0.001; plt-CD63: 28.1 % ± 1.4 % vs 8.6 % ± 0.5 %, p < 0.001). Amounts of MDMPs correlated positively with these platelet activation markers, and the relation between PDMP and MDMP was the most significant. The concentration of MDMP in patients who had diabetes complicated with nephropathy, retinopathy, or neuropathy was higher than in those without diabetes-related complications. The increase in MDMP was particularly significant in patients with nephropathy. Concentrations of sE-selectin were higher in Type II diabetes patients than in control subjects, and correlated with MDMP, PDMP, plt-CD62P, and plt-CD63 levels in nephropathy patients. Conclusion/interpretation. In Type II diabetes patients, we detected increased activation of monocytes, which could have been stimulated by activated platelets and PDMPs. Because the activation of monocytes is associated with vascular endothelial damage, high concentrations of MDMPs could indicate vascular complications in diabetes patients, especially those who have diabetes-related nephropathy. [Diabetologia (2002) 45: ▪–▪]

The effects of pitavastatin, eicosapentaenoic acid and combined therapy on platelet-derived microparticles and adiponectin in hyperlipidemic, diabetic patients.

Platelet-derived microparticles (PDMP) play an important role in the pathogenesis of diabetic vasculopathy, and statins or eicosapentaenoic acid (EPA) have been shown to have a beneficial effect on atherosclerosis in hyperlipidemic patients. However, the influence of EPA and statins on PDMP and adiponectin in atherosclerosis is poorly understood. We investigated the effect of pitavastatin and EPA on circulating levels of PDMP and adiponectin in hyperlipidemic patients with type II diabetes. A total of 191 hyperlipidemic patients with type II diabetes were divided into three groups: group A received pitavastatin 2 mg once daily (n = 64), group B received EPA 1800 mg daily (n = 55) and group C received both drugs (n = 72). PDMP and adiponectin were measured by ELISA at baseline and after 3 and 6 months of drug treatment. Thirty normolipidemic patients were recruited as healthy controls. PDMP levels prior to treatment in hyperlipidemic patients with diabetes were higher than levels in healthy controls (10.4 ± 1.9 vs. 3.1 ± 0.4 U/ml, p < 0.0001), and adiponectin levels were lower than controls (3.20 ± 0.49 vs. 5.98 ± 0.42 µg/ml, p < 0.0001). PDMP decreased significantly in group B (before vs. 6M, 10.6 ± 2.0 vs. 8.0 ± 1.7 U/ml, p < 0.01), but not in group A (before vs. 6M, 9.4 ± 1.9 vs. 9.6 ± 1.7 U/ml, not significant). In contrast, group A exhibited a significant increase in adiponectin levels after treatment (before vs. 6M, 3.29 ± 0.51 vs. 4.16 ± 0.60 µg/ml, p < 0.001). Furthermore, group C exhibited significant improvement in both PDMP and adiponectin levels after treatment (PDMP, before vs. 6M, 11.2 ± 2.0 vs. 4.5 ± 2.7 U/ml, p < 0.001; adiponectin, before vs. 6M, 3.24 ± 0.41 vs. 4.02 ± 0.70 µg/ml, p < 0.001). Reductions of PDMP in combined therapy were significantly greater than those observed with EPA alone (p < 0.05 by ANOVA). In addition, soluble CD40 ligand exhibited almost the same change as PDMP in all therapy groups. These results suggest that pitavastatin possesses an adiponectin-dependent antiatherosclerotic effect, and this drug is able to enhance the anti-platelet effect of EPA. The combination therapy of pitavastatin and EPA may be beneficial for the prevention of vascular complication in hyperlipidemic patients with type II diabetes.

Losartan and Simvastatin Inhibit Platelet Activation in Hypertensive Patients

AbstractBackground: Diabetic patients also show hypercoagulability and platelet hyperaggregability, with increased levels of platelet activation-markers such as P-selectin (CD62P) and platelet-derived microparticles. We investigated the effects of losartan and simvastatin on circulating levels of platelet activation markers, microparticles, soluble selectins, and soluble cell adhesion molecules in hypertensive and hyperlipidemic patients with or without Type 2 diabetes. Methods: The subjects included 25 normotensive healthy controls and 41 hypertensive patients. The 41 hypertensive patients were divided into three groups: group A had hypertension and hyperlipidemia (n = 11), group B had hypertension and Type 2 diabetes (n = 14), and group C had hypertension, hyperlipidemia, and diabetes (n = 16). Losartan was administered to all of the patients at a dose of 50 mg/day for 24 weeks. In addition, simvastatin was administered to the hyperlipidemic patients at a dose of 10 mg/day for 24 weeks. Results: There were significant differences in the levels of CD62P, CD63, PAC-1, platelet microparticles, endothelial microparticles, sE-selectin, and sVCAM-1 between the hypertensive patients and healthy controls. These markers were all significantly increased in hypertensive and hyperlipidemic patients with Type 2 diabetes. In hypertensive patients with diabetes, CD62P, CD63, PAC-1, platelet and endothelial microparticles, and soluble adhesion markers were all decreased by losartan monotherapy. The decrease of each marker in hypertensive and hyperlipidemic patients given combined therapy with losartan plus simvastatin was greater among those with than without Type 2 diabetes. Low-density lipoprotein was decreased significantly by simvastatin and was correlated with CD62P or platelet microparticles in all of the patients. Conclusion: Administration of losartan plus simvastatin to hypertensive and hyperlipidemic patients with Type 2 diabetes may prevent the development of cardiovascular complications caused by activated platelets and microparticles via another mechanism in addition to reduction of the blood pressure or lipid levels.

5-HT2A receptor antagonist increases circulating adiponectin in patients with type 2 diabetes.

We compared the levels of plasma adiponectin, platelet activation markers (P-selectin, CD63, PAC-1, annexin V, and platelet-derived microparticles), and endothelial injury markers (soluble E-selectin and soluble vascular cell adhesion molecule-1) in 53 patients with type 2 diabetes mellitus to investigate potential contributions to diabetic vascular complications. In addition, we administered serotonin antagonist (sarpogrelate hydrochloride) to type 2 diabetes patients who had increased soluble E-selectin levels. The concentrations of platelet activation markers and endothelial injury markers in diabetic patients were significantly higher than those in normal subjects. However, levels of adiponectin were lower in type 2 diabetes patients than in control subjects. A total of 32 patients had high-soluble E-selectin levels (soluble E-selectin ≥ 62 ng/ml); a subset of patients that also had significant elevation of platelet activation and endothelial injury markers compared with patients without high soluble E-selectin. In addition, both platelet-P-selectin and platelet-derived microparticle levels negatively correlated with the adiponectin level. Patients with high soluble E-selectin exhibited significant improvement of all markers after sarpogrelate hydrochloride treatment. These findings suggest that there is a link between vascular change in type 2 diabetes and activated platelets, endothelial dysfunction, and an adiponectin abnormality.

Effects of pitavastatin on adiponectin in patients with hyperlipidemia.

The effects of treatment with pitavastatin on inflammatory and platelet activation markers and adiponectin in 117 patients with hyperlipidemia were investigated to determine whether pitavastatin may prevent the progression of atherosclerotic changes in hyperlipidemic patients. Adiponectin levels prior to pitavastatin treatment in hyperlipidemic patients with and without diabetes were lower than levels in normolipidemic controls. Both total cholesterol and the low-density lipoprotein cholesterol decreased significantly after pitavastatin administration. Additionally, hyperlipidemic patients with or without type 2 diabetes exhibited a significant increase in adiponectin levels 6 months after pitavastatin treatment (diabetes: 3.52 ± 0.80 vs. 4.52 ± 0.71 µg/ml, p < 0.001; no diabetes: 3.48 ± 0.71 vs. 4.23 ± 0.82 µg/ml, p < 0.05). However, high-sensitivity C-reactive protein, platelet-derived microparticle and soluble P-selectin did not exhibit any differences before or after pitavastatin administration. Levels of adiponectin significantly increased after pitavastatin administration in the group of lower soluble P-selectin (soluble P-selectin before pitavastatin treatment <200 ng/ml). These results suggest that pitavastatin possesses an adiponectin-increasing effect in patients with hyperlipidemia and this effect is influenced by intensive platelet activation.

Effects of pitavastatin on monocyte chemoattractant protein-1 in hyperlipidemic patients.

The effects of statins on platelet activation markers, chemokines and adiponectin, were investigated in 135 patients with hyperlipidemia. Of the 135 hyperlipidemic patients, 63 were allocated to the simvastatin group, treated with simvastatin at the dose of 10 mg daily, and the remaining 72 were allocated to the pitavastatin group, treated with pitavastatin at the dose of 2 mg daily. Plasma levels of platelet-derived microparticles (PDMP), cell adhesion molecules (sCD40L and sP-selectin), chemokines [monocyte chemoattractant protein-1 (MCP-1) and regulated on activation normally T-cell expressed and secreted] and adiponectin were measured at the baseline and after 6 months of treatment in both the groups. In addition, we carried out a basic study to investigate the MCP-1-dependent induction of tissue factor expression on a histiocytic cell line (U937 cells). The plasma levels of PDMP, sCD40L, sP-selectin, regulated on activation normally T-cell expressed and secreted and MCP-1 were higher, whereas those of adiponectin were lower, in the hyperlipidemic patients than in the normolipidemic controls. Plasma PDMP and sCD40L were positively correlated, whereas plasma adiponectin was negatively correlated, with the plasma levels of MCP-1. No significant differences in the plasma levels of PDMP, sCD40L, sP-selectin, regulated on activation normally T-cell expressed and secreted and MCP-1 measured before and after treatment were observed in either the simvastatin or pitavastatin group. A significant increase of the plasma adiponectin levels was observed after 6 months of treatment with pitavastatin but not after an equal duration of treatment with simvastatin. When pitavastatin-treated patients were divided into two groups according to the adiponectin response to pitavastatin treatment, significant decreases of the plasma MCP-1, PDMP and sCD40L levels were observed after pitavastatin treatment in the responder group. In the aforementioned basic study, MCP-1 by itself did not induce the expression of tissue factor on the U937 cells. However, the recombinant sCD40L-induced expression of tissue factor on U937 was enhanced by the addition of MCP-1. These findings suggest that PDMP, sCD40L and MCP-1 may participate in the development of atherothrombosis in patients with hyperlipidemia and that pitavastatin may exert an adiponectin-dependent antiatherothrombotic effect in hyperlipidemic patients.

Effects of pitavastatin on plasminogen activator inhibitor-1 in hyperlipidemic patients

The effects of statins on two platelet activation markers, plasiminogen activator inhibitor (PAI)-1 and adiponectin, were investigated in 68 patients with hyperlipidemia. The patients were treated with pitavastatin with a dosage of 2 mg daily. The plasma levels of platelet-derived microparticles (PDMP), soluble CD40 ligand (sCD40L), sP-selectin, PAI-1, and adiponectin were measured at baseline and after 6 months of treatment in both groups. In hyperlipidemic patients, the plasma levels were higher in PDMP, sCD40L, sP-selectin, and PAI-1, and lower in adiponectin, compared to the normolipidemic controls. Plasma PDMP and sCD40L were positively correlated, while plasma adiponectin was negatively correlated with the plasma levels of PAI-1. No significant differences were observed in the plasma levels of PDMP, sCD40L, sP-selectin, and PAI-1 before and after treatment. A significant increase in plasma adiponectin levels was observed after 6 months of treatment with pitavastatin. When the patients treated with pitavastatin were divided into two groups according to the adiponectin response to pitavastatin treatment, significant decreases in plasma PAI-1, PDMP, and sCD40L levels were observed after pitavastatin treatment in the responder group. These findings suggest that PDMP, sCD40L, and PAI-1 may participate in the development of atherothrombosis in patients with hyperlipidemia, and that pitavastatin may exert an adiponectin-dependent anti-atherothrombotic effect in hyperlipidemic patients.

Genetic analysis of HLA, NA and HPA typing in type 2 diabetes and ASO

We examined the genetic status of human leucocyte antigens (HLA), human platelet alloantigens (HPA) and neutrophil‐specific antigens (NA) in patients with type 2 diabetes mellitus and diabetic arteriosclerosis obliterans (ASO). To our knowledge, the present study is the first report showing the relationship among three genetic factors in type 2 diabetes mellitus and ASO patients. HLA typing was performed by the polymerase chain reaction (PCR)–restriction fragment length polymorphism method. HPA‐typing and NA‐typing were by a PCR‐sequence‐specific primer method. The incidence of HLA‐DRB1*1501 was found to be significant in type 2 diabetes and non‐diabetic, particularly ASO‐positive patients, compared to control subjects. There were no differences in NA1/NA2 between the control and diabetic or non‐diabetic ASO groups. However, the frequency of NA2/NA2 in ASO‐positive diabetes and non‐diabetic ASO patients was significantly higher than controls. The a/b genotype of HPA‐5a/5b was significantly lower in type 2 diabetes and non‐diabetic ASO‐positive patients than in controls. These findings suggest that genetic studies of HLA, NA and HPA could be useful to understand the pathogenesis of type 2 diabetes and ASO.