Acute Hyperglycaemia Enhances Platelet Activation: Involvement of Multiple Mechanisms.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3884-3884
Author(s):  
Nailin Li ◽  
Dzana Sudic ◽  
Mikael Forslund ◽  
Masoud Razmara
Keyword(s):  
Platelet Activation ◽  
Whole Blood ◽  
Acute Hyperglycemia ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Kinase C ◽  
Fibrinogen Binding ◽  
Impedance Aggregometry ◽  
Leukocyte Aggregation

Abstract Diabetes mellitus is associated with platelet dysfunction, and hypoglycemic treatments may counteract this diabetic alteration. We thus studied how acute hyperglycemia influences platelet function. Fast blood (n=20) was incubated with different levels of glucose (5, 15, and 30 mM) for 5 min, and without or with in vitro stimuli. Platelet activation was monitored by whole blood flow cytometry, while platelet aggregation was also measured using impedance aggregometry. Blood glucose levels had little influence on unstimulated platelets. Hyperglycemia enhanced ADP- and TRAP-induced platelet P-selectin expression. Hyperglycemia also increased TRAP-induced platelet fibrinogen binding. High glucose levels mildly increased ADP- and TRAP-induced platelet-leukocyte aggregation. The blockade of protein kinase C (PKC) slightly attenuated ADP-induced, and markedly inhibited TRAP-induced platelet activation. PKC blockade had, however, little effect on hyperglycemia effect. Platelet P-selectin expression induced by the direct PKC activator phorbol 12-myristate 13-acetate (PMA) was not augmented by hyperglycemia. Superoxide anion scavenging by superoxide dismutase (SOD) reduced, whistle cyclo-oxygenase (COX) inhibition by naproxen did not reduced the enhancing effect of platelet activation by hyperglycemia. In conclusion, acute hyperglycemia enhances platelet activation in whole blood. Superoxide anions contribute importantly to hyperglycemia-enhanced platelet activation, while other mechanisms not identified presently also contribute to hyperglycemic effects.

Activated Akt Is Associated with Hyperglycemia and Platelet Hyperactivity in a Mouse Model of Diabetes

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5360-5360
Author(s):  
Lin Lu ◽  
Donna Woulfe
Keyword(s):  
Blood Glucose ◽  
Mouse Model ◽  
Platelet Activation ◽  
Diabetic Patients ◽  
Type I ◽  
Platelet Activity ◽  
Akt Phosphorylation ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Fibrinogen Binding

Abstract Platelet hyperactivation has been reported in patients with both Type I and Type II diabetes mellitus and likely contributes to the increased prevalence of thrombotic complications in diabetic patients. However, the mechanisms leading to platelet hyperactivity in diabetes are not fully understood. Our previous studies showed that the Akt signaling pathway positively regulates platelet activity. Here, we evaluate the effect of hyperglycemia on Akt phosphorylation and platelet activation using a Type I diabetic mouse model. Hyperglycemia was induced by intraperitoneal injection of streptozotocin (STZ 50mg/kg for 5 days) in C57BL/6 mice. Blood glucose levels were elevated in 12 mice 4 weeks after STZ injection (mean ± SD: 410 ± 70 mg/ml) compared with 11 mice without STZ injection (212 ± 50 mg/ml). Platelets from hyperglycemic mice showed enhanced agonist-dependent aggregation (max % aggregation: 58% ± 10% in hyperglycemia versus 0% in normoglycemia at 0.6mM AYPGKF, n=3 each), fibrinogen binding (62.2% fibrinogen-bound cells ± 5.4% in hyperglycemic conditions versus 46.1% ± 16.3% in normoglycemia at 2mM AYPGKF) and P-selectin binding (42.1% cells with surface P-selectin ± 3.7% in hyperglycemic platelets, 25.3% ± 5.9% in normoglycemia at 2mM AYPGKF) compared with platelets from mice with normal glucose levels. The blood glucose levels were directly correlated with Alexafluor-fibrinogen binding (r=0.65, p=0.042) when platelets were stimulated with thrombin receptor agonist peptide AYPGKF (1.5mM), and also directly correlated with P-selectin surface exposure (r=0.95, p=0.003) after platelets were stimulated with 1.5mM AYPGKF. To determine whether the Akt pathway is involved in enhanced platelet activation in diabetes, we tested phosphorylation of Akt ser473 by immunoblotting. Akt phosphorylation of this residue was increased (35% ± 4%) in platelets from hyperglycemic mice compared with platelets from nondiabetic mice. In conclusion, platelets from hyperglycemic mice are more sensitive to PAR4 agonist-induced fibrinogen binding and P-selectin exposure compared with nondiabetic platelets. Enhanced activation of Akt in platelets under hyperglycemic conditions may play a role in platelet hyperactivation in diabetes.

Contrast medium attenuates platelet activation and platelet-leukocyte cross–talk

2005 ◽  
Vol 93 (05) ◽  
pp. 922-926
Author(s):  
Qiushang Ji ◽  
Melania Ghaly ◽  
Paul Hjemdahl ◽  
Per Tornvall ◽  
Nailin Li
Keyword(s):  
Platelet Activation ◽  
Cross Talk ◽  
Whole Blood ◽  
Leukocyte Activation ◽  
Cd11b Expression ◽  
Blood Samples ◽  
Fibrinogen Binding ◽  
Ionic Contrast ◽  
Leukocyte Aggregation ◽  
The Impact

SummaryThe influence of ionic and non-ionic contrast media (CM) on platelet and leukocyte activation and platelet-leukocyte crosstalk was investigated in hirudinized whole blood. The blood was incubated with and without the ionic CM ioxaglate and the nonionic CM iodixanol at 37ºC for 5 min, without or with stirring. Platelet and leukocyte activation and platelet-leukocyte aggregation were measured using whole blood flow cytometry. When blood samples were pre-incubated in the presence of 2%, 5%, and 10% of CM without stirring, both ioxaglate and iodixanol had little effect on unstimulated samples, but dose-independently decreased 1 μM ADP-induced platelet P-selectin expression and fibrinogen binding, and thus platelet-leukocyte aggregate formation. Ioxaglate had little effect on leukocyte CD11b expression, whilst iodixanol slightly enhanced resting and N-formyl-methionyl-leucyl-phenylalanine (fMLP; 0.1 μM)-stimulated leukocyte CD11b expression. Blood samples were also incubated with stirring to investigate the impact of CM (5% of ioxaglate or iodixanol) on platelet-leukocyte cross-talk. Collagen induced marked platelet activation and platelet-leukocyte aggregation, and subsequently elevated leukocyte CD11b expression. The latter was attenuated by ioxaglate and iodixanol, and was accompanied by reduced platelet-leukocyte aggregation. In conclusion, the CM ioxaglate and iodixanol attenuate platelet activation and platelet-leukocyte cross-talk. Inhibitory effects of the contrast agents on this cross-talk are apparently exerted by reducing heterotypic conjugation, and may be beneficial in connection with PCI.

A Simple and Rapid Method to Determine GPIIb/IIIa-Receptor Inhibitor Activity in Whole Blood

1999 ◽  
Vol 19 (03) ◽  
pp. 134-138
Author(s):  
Gitta Kühnel ◽  
A. C. Matzdorff
Keyword(s):  
Flow Cytometry ◽  
Platelet Count ◽  
Blood Sample ◽  
Platelet Activation ◽  
Whole Blood ◽  
Receptor Occupancy ◽  
Aggregate Formation ◽  
Inhibitor Activity ◽  
Receptor Inhibitor

SummaryWe studied the effect of GPIIb/IIIa-inhibitors on platelet activation with flow cytometry in vitro. Citrated whole blood was incubated with increasing concentrations of three different GPIIb/IIIa-inhibitors (c7E3, DMP728, XJ757), then thrombin or ADP were added and after 1 min the sample was fixed. Samples without c7E3 but with 0.1 U/ml thrombin had a decrease in platelet count. Samples with increasing concentrations of c7E3 had a lesser or no decrease in platelet count. The two other inhibitors (DMP 725, XJ757) gave similar results. GPIIb/IIIa-inhibitors prevent aggregate formation and more single platelets remain in the blood sample. The agonist-induced decrease in platelet count correlates closely with the concentration of the GPIIb/IIIa inhibitor and receptor occupancy. This correlation may be used as a simple measure for inhibitor activity in whole blood.

Intensive Insulin Therapy for Acute Hyperglycemia

2007 ◽  
Vol 18 (2) ◽  
pp. 200-212
Author(s):  
Julia Lindeman Read ◽  
Eugene Y. Cheng
Keyword(s):  
Insulin Therapy ◽  
Critically Ill ◽  
Intensive Insulin Therapy ◽  
Organ Damage ◽  
Tight Glycemic Control ◽  
Critically Ill Patient ◽  
Acute Hyperglycemia ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Therapy Protocol

There is growing evidence that control of hyperglycemia in the critically ill patient improves outcome. Normalizing blood glucose levels decreases the risk of developing sepsis, end-organ damage, and hospital mortality. Critical care clinicians must be familiar with current and benchmark research supporting control of hyperglycemia and use this knowledge to ensure appropriate application of evidence-based practice for decreasing or preventing complications in the critically ill patient. This article describes the effects of hyperglycemia and discusses the evidence supporting tight glycemic control in such patients. The necessary steps to implement an intensive insulin therapy protocol for control of acute hyperglycemia are detailed.

Chenopodium quinoa Exhibits Antihyperglycemic Activity in Streptozotocin-Induced Diabetic Rats

2021 ◽  
Vol 19 ◽  
Author(s):  
Amine Azzane ◽  
Ayou Amssayef ◽  
Mohame Eddouks
Keyword(s):  
Antioxidant Activity ◽  
Aqueous Extract ◽  
Histopathological Examination ◽  
Chenopodium Quinoa ◽  
Diabetic Rats ◽  
Favorable Effect ◽  
Antihyperglycemic Activity ◽  
Glucose Levels ◽  
Blood Glucose Levels

Aims: The aim of the study was to evaluate the antihyperglycemic effect of Chenopodium quinoa. Background: Chenopodium quinoa is a pseudocereal plant with several medicinal properties. Objective: The goal of this investigation was to determine the antihyperglycemic activity of Chenopodium quinoa in both normal and streptozotocin(STZ)-induced diabetic rats. Methods: In this study, the effect of the aqueous extract of Chenopodium quinoa seeds (AECQS) (60 mg/kg) on blood glucose levels was evaluated in both normal and diabetic rats after a single (6 hours) and repeated oral administration (7 days of treatment). The effect of this herb on glucose tolerance and lipid profile was also studied. Additionally, histopathological examination of liver was carried out using the Hematoxylin-Eosin method. Furthermore, the in vitro antioxidant activity as well as a preliminary phytochemical screening and quantification of some secondary metabolites (phenolic compounds, flavonoids and tannins) were performed according to standard methods. Results: AECQS produced a significant lowering effect on plasma glucose levels in STZ-induced diabetic rats. In addition, this extract exhibited a remarkable amelioration on hepatic histopathology in diabetic rats. In addition, the extract exerted a remarkable antioxidant activity which could be due to the presence of some compounds found in this herb. Conclusion: In conclusion, this study demonstrates that the aqueous extract of Chenopodium quinoa seeds has a favorable effect in controlling diabetes mellitus.

Determinants of platelet conjugate formation with polymorphonuclear leukocytes or monocytes in whole blood

2007 ◽  
Vol 98 (12) ◽  
pp. 1276-1284 ◽  
Author(s):  
Simona Costanzo ◽  
Branislav Vohnout ◽  
Licia Iacoviello ◽  
Giovanni de Gaetano ◽  
Benedetta Izzi ◽  
...  
Keyword(s):  
Platelet Count ◽  
Whole Blood ◽  
Polymorphonuclear Leukocytes ◽  
Large Population ◽  
Mixed Cell ◽  
Cd11b Expression ◽  
Glucose Levels ◽  
Primary Platelet ◽  
Collagen Stimulation

SummaryFollowing preliminary in-vitro experiments, platelet-leukocyte conjugates and their determinants were evaluated in citrated whole blood from 349 subjects (209 women, age 16–92 years) randomly recruited from the general population. Platelet activation by ADP/collagen but not leukocyte stimulation by fMLP or LTB4 resulted in formation of platelet conjugates with PMN or monocytes. In the population study, mixed cell conjugates, platelet P-selectin and leukocyte CD11b were measured by flow cytometry both at baseline and after in-vitro stimulation with ADP/collagen. The latter significantly increased platelet conjugates with either PMN or monocytes, platelet P-selectin and leukocyte CD11b expression. Platelet count significantly correlated with platelet-PMN, platelet-monocyte conjugates and P-selectin both at baseline and upon stimulation. In all conditions, both conjugate levels correlated with each other, when adjusted for gender, age and platelet count. Age correlated with platelet-PMN conjugate numbers in basal and stimulated conditions and with basal P-selectin. ADP/collagen stimulation resulted in higher P-selectin and conjugates values in women. Among risk factors, a significant correlation was found between conjugate and glucose levels. In conclusion, the presence and formation in whole blood from a large population of plateletleukocyte conjugates reflects primary platelet – but not leukocyte – activation and varies with gender, age, platelet count and blood glucose.

scholarly journals Oral DhHP-6 for the Treatment of Type 2 Diabetes Mellitus

2019 ◽  
Vol 20 (6) ◽  
pp. 1517 ◽  
Author(s):  
Kai Wang ◽  
Yu Su ◽  
Yuting Liang ◽  
Yanhui Song ◽  
Liping Wang
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Blood Glucose ◽  
Enzymatic Activity ◽  
Glucose Levels ◽  
Blood Glucose Levels

Type 2 diabetes mellitus (T2DM) is associated with pancreatic β-cell dysfunction which can be induced by oxidative stress. Deuterohemin-βAla-His-Thr-Val-Glu-Lys (DhHP-6) is a microperoxidase mimetic that can scavenge reactive oxygen species (ROS) in vivo. In our previous studies, we demonstrated an increased stability of linear peptides upon their covalent attachment to porphyrins. In this study, we assessed the utility of DhHP-6 as an oral anti-diabetic drug in vitro and in vivo. DhHP-6 showed high resistance to proteolytic degradation in vitro and in vivo. The degraded DhHP-6 product in gastrointestinal (GI) fluid retained the enzymatic activity of DhHP-6, but displayed a higher permeability coefficient. DhHP-6 protected against the cell damage induced by H2O2 and promoted insulin secretion in INS-1 cells. In the T2DM model, DhHP-6 reduced blood glucose levels and facilitated the recovery of blood lipid disorders. DhHP-6 also mitigated both insulin resistance and glucose tolerance. Most importantly, DhHP-6 promoted the recovery of damaged pancreas islets. These findings suggest that DhHP-6 in physiological environments has high stability against enzymatic degradation and maintains enzymatic activity. As DhHP-6 lowered the fasting blood glucose levels of T2DM mice, it thus represents a promising candidate for oral administration and clinical therapy.

Juxtamedullary microvascular dysfunction during the hyperfiltration stage of diabetes mellitus

1994 ◽  
Vol 267 (1) ◽  
pp. F99-F105 ◽  
Author(s):  
K. Ohishi ◽  
M. I. Okwueze ◽  
R. C. Vari ◽  
P. K. Carmines
Keyword(s):  
Diabetes Mellitus ◽  
Microvascular Dysfunction ◽  
Sprague Dawley ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Sprague Dawley Rats ◽  
Vasoconstrictor Response ◽  
Wide Range ◽  
Single Nephron

This study was designed to identify and localize defects in renal microvascular function during the hyperfiltration stage of diabetes mellitus. Male Sprague-Dawley rats were injected intravenously with 65 mg/kg streptozotocin (IDDM rats) or vehicle (sham rats). IDDM rats received insulin (3 U.kg-1.day-1) via an osmotic minipump; sham rats received diluent. During the ensuing 2-wk period, blood glucose levels averaged 89 +/- 2 mg/dl in 33 sham rats and 290 +/- 13 mg/dl in 37 IDDM rats. At the end of this period, inulin clearance was elevated in eight IDDM rats (1.43 +/- 0.17 ml.min-1.g kidney wt-1) compared with six sham rats (0.78 +/- 0.05 ml.min-1.g kidney wt-1). The remaining animals served as tissue donors for study of the renal microvasculature using the in vitro blood-perfused juxtamedullary nephron technique. Kidneys from sham and IDDM rats were perfused with homologous blood at a renal arterial pressure of 110 mmHg. Juxtamedullary single-nephron glomerular filtration rate was higher in IDDM rats (41.5 +/- 5.4 nl/min) than in sham rats (25.4 +/- 2.4 nl/min). Afferent arteriolar inside diameter was greater in IDDM rats (34 +/- 2 microns) than in sham rats (22 +/- 1 microns); however, efferent arteriolar diameter did not differ between groups. The afferent arteriolar vasoconstrictor response to norepinephrine (NE) was attenuated in IDDM rats, relative to sham rats, over a wide range of NE concentrations. In contrast, NE evoked similar degrees of efferent vasoconstriction in IDDM and sham rats.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Baking Effect on Resistant Starch Digestion from Composite Bread Produced with Partial Wheat Flour Substitution

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Rafael Grassi de Alcântara ◽  
Heidge Fukumasu ◽  
Paulo Cesar Fabricio Raspantini ◽  
Leonila Ester Reinert Raspantini ◽  
Caroline Joy Steel ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Wheat Flour ◽  
Resistant Starch ◽  
Composite Flour ◽  
Corn Flour ◽  
Glucose Levels ◽  
Baked Goods ◽  
Blood Glucose Levels ◽  
Green Banana

The consumption of composite flour, such as green banana and corn flour, is related to maintain stable blood glucose levels, due to high resistant starch levels. However, most of these studies have conducted analyses of unprocessed food such as flour. Therefore, this study aimed to evaluate the effect of baking on resistant starch concentration and digestion from bread produced with partial wheat flour substitution. Response surface methodology was used to evaluate bread physical-chemical characteristics, and then, sensorial and nutritional qualities of the bread were evaluated. The feasibility of incorporating 40% of corn flour was demonstrated, while incorporation of 20% produced bread with similar characteristics to the control; for green banana flour, these levels were 20 and 10%, respectively. Resistant starch levels of composite breads were also enhanced by in vitro analyses. On the other hand, in vivo blood glucose levels evidenced that the ingestion of breads produced with partial wheat flour substitution by green banana or corn flour promoted a more important peak in blood glucose levels in comparison with control bread, which was never previously presented in the literature. Bread ingestion rapidly increased the blood glucose levels of rats; once during the baking process, starch granules become gelatinized and therefore easily digestible. Furthermore, this study also highlighted the lack and need for future investigation of wheat flour-substituted baked goods, in order to better understand mechanical properties formation and also product digestibility.

scholarly journals Glycemic Variability in Diabetes Increases the Severity of Influenza

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Rebecca J. Marshall ◽  
Pornthida Armart ◽  
Katina D. Hulme ◽  
Keng Yih Chew ◽  
Alexandra C. Brown ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glycemic Variability ◽  
Endothelial Barrier ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Severe Influenza ◽  
Increased Risk ◽  
History Of

ABSTRACT People with diabetes are two times more likely to die from influenza than people with no underlying medical condition. The mechanisms underlying this susceptibility are poorly understood. In healthy individuals, small and short-lived postprandial peaks in blood glucose levels occur. In diabetes mellitus, these fluctuations become greater and more frequent. This glycemic variability is associated with oxidative stress and hyperinflammation. However, the contribution of glycemic variability to the pathogenesis of influenza A virus (IAV) has not been explored. Here, we used an in vitro model of the pulmonary epithelial-endothelial barrier and novel murine models to investigate the role of glycemic variability in influenza severity. In vitro, a history of glycemic variability significantly increased influenza-driven cell death and destruction of the epithelial-endothelial barrier. In vivo, influenza virus-infected mice with a history of glycemic variability lost significantly more body weight than mice with constant blood glucose levels. This increased disease severity was associated with markers of oxidative stress and hyperinflammation both in vitro and in vivo. Together, these results provide the first indication that glycemic variability may help drive the increased risk of severe influenza in people with diabetes mellitus. IMPORTANCE Every winter, people with diabetes are at increased risk of severe influenza. At present, the mechanisms that cause this increased susceptibility are unclear. Here, we show that the fluctuations in blood glucose levels common in people with diabetes are associated with severe influenza. These data suggest that glycemic stability could become a greater clinical priority for patients with diabetes during outbreaks of influenza.

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