| 1. |
- Bergdahl, Andreas, et al.
(författare)
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Plasticity of TRPC expression in arterial smooth muscle: correlation with store-operated Ca2+ entry.
- 2005
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Ingår i: American Journal of Physiology: Cell Physiology. - : American Physiological Society. - 1522-1563 .- 0363-6143. ; 288:4, s. 872-880
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Tidskriftsartikel (refereegranskat)abstract
- Loss of the smooth muscle contractile phenotype is critical in atherosclerosis and in restenosis after angioplasty, but its early signals are incompletely understood. In this study, we have explored the role of transient receptor potential canonical (TRPC) proteins, which have been suggested to mediate store-operated Ca2+ entry (SOCE). Contractility of rat cerebral arteries in organ culture is preserved for several days, whereas SOCE is increased. In correlation with this increase is that nifedipine-insensitive whole cell current, activated by depletion of intracellular Ca2+ stores, was increased by 50% in cells isolated from arteries cultured for 3 days. TRPC1 and TRPC6 mRNA were more than fivefold increased in cells isolated after organ culture, whereas TRPC3 was decreased. Immunofluorescent staining and/or Western blotting of arteries and isolated cells showed upregulation of TRPC1 and TRPC6 proteins during organ culture. In intact arteries, TRPC4 expression correlated with the amount of endothelium present. Ca2+ addition after store depletion caused a contraction in cultured, but not in freshly dissected, arteries. A polyclonal TRPC1 antibody directed against an extracellular epitope inhibited this contraction by approximately 50%. To investigate the basis of the TRPC upregulation and assess its possible clinical significance, segments of human internal mammary artery were organ cultured for 24 h and then exposed to balloon dilatation in vitro, followed by further culturing for up to 48 h. After dilatation, TRPC1 and TRPC6 mRNA were progressively increased compared with undilated control segments. The results of this study indicate that vascular injury enhances plasticity in TRPC expression, that TRPC expression correlates with cellular Ca2+ handling, and that TRPC1 is a subunit of upregulated store-operated Ca2+ channels.
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| 2. |
- Braun, Oscar, et al.
(författare)
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Residual platelet ADP reactivity after clopidogrel treatment is dependent on activation of both the unblocked P2Y(1) and the P2Y (12) receptor and is correlated with protein expression of P2Y (12).
- 2007
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Ingår i: Purinergic Signalling. - : Springer Science and Business Media LLC. - 1573-9546 .- 1573-9538. ; 3:3, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- Two ADP receptors have been identified on human platelets: P2Y(1) and P2Y(12). The P2Y(12) receptor blocker clopidogrel is widely used to reduce the risks in acute coronary syndromes, but, currently, there is no P2Y(1) blocker in clinical use. Evidence for variable responses to clopidogrel has been described in several reports. The mechanistic explanation for this phenomenon is not fully understood. The aim of this study was to examine mechanisms responsible for variability of 2MeS-ADP, a stable ADP analogue, induced platelet reactivity in clopidogrel-treated patients. Platelet reactivity was assessed by flow cytometry measurements of P-selectin (CD62P) and activated GpIIb/IIIa complex (PAC-1). Residual 2MeS-ADP activation via the P2Y(12) and P2Y(1) receptors was determined by co-incubation with the selective antagonists AR-C69931 and MRS2179 in vitro. P2Y(1) and P2Y(12) receptor expression on both RNA and protein level were determined, as well as the P2Y(12) H1 or H2 haplotypes. Our data suggest that the residual platelet activation of 2MeS-ADP after clopidogrel treatment is partly due to an inadequate antagonistic effect of clopidogrel on the P2Y(12) receptor and partly due to activation of the P2Y(1) receptor, which is unaffected by clopidogrel. Moreover, a correlation between increased P2Y(12) protein expression on platelets and decreased response to clopidogrel was noticed, r(2)=0.43 (P<0.05). No correlation was found between P2Y(12) mRNA levels and clopidogrel resistance, indicating post-transcriptional mechanisms. To achieve additional ADP inhibition in platelets, antagonists directed at the P2Y(1) receptor could be more promising than the development of more potent P2Y(12) receptor antagonists.
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| 3. |
- Alfredsson, Joakim
(författare)
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Management and Outcome in Non ST-Elevation Acute Coronary Syndromes : Similarities and Differences Between Women and Men
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Non ST-elevation Acute Coronary Syndromes are the most frequent manifestations of acute ischemic heart disease. Gender differences in treatment intensity, including differences in level of care, have been reported. Also differences in benefit from certain treatments, especially invasive treatment, have been discussed. Finally, difference in outcome between men and women, have been proposed. Results have been inconsistent, partly depending on if and how adjustment for differences in background characteristics has been made. The aims of the studies in this thesis were to assess differences between the genders in baseline characteristics, level of care, medical treatment and non-invasive and invasive cardiac procedures. The aims were also to determine gender differences in short and long-term mortality, including impact of level of care, and to determine differences between the genders in benefit from an invasive strategy, with special reference to benefit in women.Method: We used prospectively collected data from the RIKS-HIA registry in two studies (Paper I and IV). In one study we merged data from patients admitted to general wards in the south-east region of Sweden (The AKUT registry), with data from patients admitted to CCU´s (RIKS-HIA) at participating hospitals during the same time (Paper II). We also randomly assigned women to a routine invasive or a selective invasive treatment strategy, and performed a meta-analysis, to determine gender differences in benefit from a routine invasive strategy (Paper III).Results: Women were older than men and more likely to have a history of diabetes and hypertension, while men were more likely to have a history of myocardial infarction and revascularisation. Women were also more likely to have normal coronary arteries on the angiogram. After adjustment for baseline differences there were only minor, and directionally inconsistent, differences between women and men in pharmacological treatment. Men were more often referred for coronary angiography, even after adjustment. While CABG-rate was lower in women, after adjustment PCI-rate was similar or even higher compared to men. After adjustment for differences in age, longterm outcome was better in women. In our small but randomised trial there was no benefit from a routine invasive strategy in women. A meta-analysis indicated interaction between gender and treatment strategy, with lack of benefit in women, in contrast to in men. However, our large observational study indicated no gender difference with an invasive strategy. Moreover, benefit was similar in women and men with invasive treatment.Conclusion: There are substantial differences between women and men in baseline characteristics that affect management and outcome more than gender per se. After adjustment women have better long-term outcome than men. There appear to be a difference in benefit from a routine invasive strategy between the genders, with less benefit in women, but in routine clinical management there was no difference between women and men managed with an invasive strategy.
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| 5. |
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| 6. |
- Amisten, Stefan, et al.
(författare)
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Gene expression profiling for the identification of G-protein coupled receptors in human platelets
- 2008
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Ingår i: Thrombosis Research. - : Elsevier BV. - 1879-2472 .- 0049-3848. ; 122:1, s. 47-57
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION AND MATERIALS AND METHODS: G-protein coupled receptors (GPCRs) play an important role in platelet aggregation. To identify new platelet GPCRs, a platelet gene expression profile was generated and validated using quantitative real-time PCR. RESULTS: In total, mRNA of 28 GPCR genes was detected in human platelets. The 12 most abundant platelet GPCR transcripts were: thrombin receptor PAR1 (1865+/-178%), ADP receptor P2Y(12) (459+/-88%), succinate receptor 1 (257+/-48%), ADP receptor P2Y(1) (100%), orphan P2RY(10) (68.2+/-3.3%), lysophosphatidic acid receptors GPR23 (48.2+/-11%) and GPR92 (26.1+/-3.3%), adrenergic receptor alpha(2A) (18.4+/-4.4%), orphan EBI2 (6.31+/-0.42), adenosine receptors A(2A) (2.94+/-0.24%) and A(2B) (2.88+/-0.16%) and lysophosphatidic acid receptor LPA(1) (2.59+/-0.39%) (% relative to the chosen calibrator P2Y(1)). A surprising G-protein coupled receptor redundancy was found: two ADP receptors (P2Y(1) and P2Y(12)), three adenosine receptors (A(2A), A(2B), and A(1)), four lysophosphatidic acid receptors (LPA(1), LPA(3), GPR23 and GPR92), two l-glutamate receptors (mGlu(3) and mGlu(4)) and two serotonin receptors (5-HT(1F) and 5-HT(4)). The adenosine receptor A(2B) gene expression was validated with protein expression and functional studies. Western blot confirmed A(2B) receptor protein expression and platelet flow cytometry demonstrated inhibition of the effect of NECA by the adenosine A(2B)-antagonist MRS1754. CONCLUSIONS: We have detected several GPCRs not previously known to be expressed in platelets, including a functional adenosine A(2B) receptor. The findings could improve our understanding of platelet aggregation and provide new targets for drug development.
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| 7. |
- Amisten, Stefan, et al.
(författare)
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Increased risk of acute myocardial infarction and elevated levels of C-reactive protein in carriersof the Thr-87 variant of the ATP receptor P2Y11.
- 2007
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 28:1, s. 13-18
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Tidskriftsartikel (refereegranskat)abstract
- Aims Extracellular ATP acting on the P2Y(11) receptor regulates inflammatory cells. We hypothesized that polymorphisms in the receptor could influence the risk of acute myocardial infarction (AMI). Methods and results In the Malmo diet and cancer AMI case-control study (n = 3732) the P2Y(11) gene Thr-87 polymorphism was present in 19.8% of the controls and 22.9% in AMI patients (OR 1.21; P = 0.03). Stronger associations were found in patients with family history (FH) of AMI, 1.32; early-onset (EO) AMI, 1.43; or EO AMI combined with FH, 1.50; supporting a genetic mechanism. The Thr-87 homozygotes had an even greater risk of AMI, 1.94 (P = 0.04); and 2.48 in the EO AMI subgroup, suggesting a genetic dosage effect. In the cardiovascular risk factor group (n = 6055), 21.3% carried the Thr-87 allele. C-reactive protein was elevated in Thr-87 carriers: 1.6 mg/L vs. 1.3 mg/L (P = 0.001). No difference was seen for blood pressure, lipids, body mass index, smoking, or diabetes mellitus. Conclusion The common Ala-87-Thr polymorphism of the P2Y(11) receptor is associated with AMI and increased levels of C-reactive protein. We hypothesize that an inflammatory mechanism might be involved. The P2Y(11) receptor is a promising new drug target in the prevention of AMI.
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| 8. |
- Amisten, Stefan, et al.
(författare)
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The P2Y(13) Met-158-Thr Polymorphism, Which Is in Linkage Disequilibrium with the P2Y(12) Locus, Is Not Associated with Acute Myocardial Infarction.
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: The aims of this study were to investigate (1) if P2Y(12) polymorphisms defining the P2Y(12) H2 allele are associated with any other SNPs that may explain the previously reported association with increased ADP induced platelet activation and association with peripheral arterial disease and coronary artery disease and (2) if such variants are associated with acute myocardial infarction (AMI) or classical risk factors for AMI. METHODS AND RESULTS: The P2Y(13) Met-158-Thr polymorphism was found to be in linkage disequilibrium (LD) with the P2Y(12) H2 haplotype (all examined SNPs: D' = 1.0, r(2) = 0.936-1.0), defining a novel P2Y(12) H2/P2Y(13) Thr-158 haplotype. Genotyping of an AMI case control population (n = 1244 cases, 2488 controls) revealed no association of the P2Y(13) Thr-158 allele with AMI (OR = 0.96, 95% C.I. 0.82-1.12, P = 0.63). Also, no differences between the genotype frequencies of P2Y(13) Met-158-Met and Met-158-Thr/Thr-158-Thr were seen in AMI case-control subpopulations (early onset AMI OR = 1.06, 95% C.I. 0.85-1.31, P = 0.62); family history of AMI (OR = 0.98, 95% C.I. 0.78-1.22, P = 0.83) nor in early onset AMIs with family history of AMI (OR = 1.0, 95% C.I. 0.74-1.36, P = 1.0). Genotyping of the P2Y(13) Met-158-Thr polymorphism in a population based sample (n = 6055) revealed no association with cardiovascular risk factors. In addition, the P2Y(13) Met-158-Thr polymorphism was genotyped in a diabetes case-control population, and associations were found neither with DM nor with any examined DM risk factors. CONCLUSION GENOTYPING: The P2Y(13) Met-158-Thr polymorphism is in tight LD with the P2Y(12) locus but is not associated with AMI or classical cardiovascular risk factors.
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| 9. |
- Balogh, Johanna, et al.
(författare)
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Phospholipase C and cAMP-dependent positive inotropic effects of ATP in mouse cardiomyocytes via P2Y(11)-like receptors.
- 2005
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Ingår i: Journal of Molecular and Cellular Cardiology. - : Elsevier BV. - 1095-8584 .- 0022-2828. ; 39:2, s. 223-230
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Tidskriftsartikel (refereegranskat)abstract
- ATP is released as a cotransmitter together with catecholamines from sympathetic nerves. In the heart ATP has been shown to cause a pronounced positive inotropic effect and may also act in synergy with β-adrenergic agonists to augment cardiomyocyte contractility. The aim of the present study was to investigate the inotropic effects mediated by purinergic P2 receptors using isolated mouse cardiomyocytes. Stable adenine nucleotide analogs were used and the agonist rank order for adenine nucleotide stimulation of the mouse cardiomyocytes was AR-C67085 > ATPγS > 2-MeSATP >>> 2-MeSADP = 0, that fits the agonist profile of the P2Y11 receptor. ATPγS induced a positive inotropic response in single mouse cardiomyocytes. The response was similar to that for the β1 receptor agonist isoproterenol. The most potent response was obtained using AR-C67085, a P2Y11 receptor agonist. This agonist also potentiated contractions in isolated trabecular preparations. The adenylyl cyclase blocker (SQ22563) and phospholipase C (PLC) blocker (U73122) demonstrated that both pathways were required for the inotropic response of AR-C67085. A cAMP enzyme immunoassay confirmed that AR-C67085 increased cAMP in the cardiomyocytes. These findings are in agreement with the P2Y11 receptor, coupled both to activation of IP3 and cAMP, being a major receptor for ATP induced inotropy. Analyzing cardiomyocytes from desmin deficient mice, Des–/–, with a congenital cardiomyopathy, we found a lower sensitivity to AR-C67085, suggesting a down-regulation of P2Y11 receptor function in heart failure. The prominent action of the P2Y11 receptor in controling cardiomyocyte contractility and possible alterations in its function during cardiomyopathy may suggest this receptor as a potential therapeutic target. It is possible that agonists for the P2Y11 receptor could be used to improve cardiac output in patients with circulatory shock and that P2Y11 receptor antagonist could be beneficial in patients with congestive heart failure (CHF).
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| 10. |
- Braun, Oscar, et al.
(författare)
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Greater reduction of platelet activation markers and platelet-monocyte aggregates by prasugrel compared to clopidogrel in stable coronary artery disease
- 2008
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Ingår i: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 100:4, s. 626-633
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Tidskriftsartikel (refereegranskat)abstract
- Prasugrel, a novel P2Y(12) ADP-receptor antagonist, has been reported to achieve greater inhibition of platelet aggregation compared to clopidogrel as assessed by light transmission aggregometry. It was the objective of this study to investigate the effect of prasugrel on alternative markers of platelet activation in comparison to a high loading dose and the approved maintenance dose of clopidogrel. One hundred ten aspirin-treated patients with stable coronary artery disease were randomized to a loading dose (LD, day 1)/ maintenance dose (MD, days 2-29) of prasugrel 60 mg/10 mg or clopidogrel 600 mg/75 mg. Platelet activation markers were analyzed by whole blood flow cytometry pre-dose and at 2 and 24 hours after LD and pre-dose at 14 and 29 days. After stimulation with 20 muM ADP, 2 hours after LD, significantly lower expression of activated GPIIb/IIIa (4.3 vs. 21.8 [mean fluorescent intensity (MFI)], p < 0.001) and P-selectin (2.0 vs. 11.7 MFI, p < 0.001) along with decreased formation of platelet-monocyte aggregates (16.4% vs. 29.6% positive cells, p < 0.001) was observed with prasugrel versus clopidogrel. All these effects were maintained through 24 hours and during the MD period. In conclusion, prasugrel 60 mg LD and 10 mg MD inhibit several markers of platelet activation and the formation of platelet-monocyte aggregates more effectively than a 600 mg LD and 75 mg MD of clopidogrel. Attenuated platelet aggregation and reduced expression of platelet pro-coagulant and pro-inflammatory markers with prasugrel suggest the potential to reduce cardiovascular events both in the acute setting and in long-term treatment.
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