1
|
Gallieni M, De Salvo C, Lunati ME, Rossi A, D'Addio F, Pastore I, Sabiu G, Miglio R, Zuccotti GV, Fiorina P. Continuous glucose monitoring in patients with type 2 diabetes on hemodialysis. Acta Diabetol 2021; 58:975-981. [PMID: 33743082 PMCID: PMC8272699 DOI: 10.1007/s00592-021-01699-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/27/2021] [Indexed: 12/14/2022]
Abstract
Diabetic kidney disease is the leading cause of end-stage kidney disease in high-income countries. The strict control of glycemic oscillations is the principal therapeutic target, but this could be hard to achieve in uremic patients due to their unpredictable insulin sensitivity. Currently, the evaluation of the glycemic profile relies on serum markers (glycated hemoglobin HbA1c, glycated albumin, and fructosamine), capillary glucose blood control (self-monitoring of blood glucose), and interstitial glucose control (continue glucose monitoring). We conducted a systematic review of published articles on continue glucose monitoring in hemodialysis patients with type 2 diabetes, which included 12 major articles. Four studies found significant fluctuations in glucose levels during hemodialysis sessions. All studies reported a higher mean amplitude of glucose variations on the hemodialysis day. Three studies agreed that continue glucose monitoring is better than glycated hemoglobin in detecting these abnormalities. Moreover, continue glucose monitoring was more accurate and perceived as easier to use by patients and their caregivers. In patients with type 2 diabetes on hemodialysis, glucose levels show different variation patterns than the patients on hemodialysis without diabetes. Considering manageability, accuracy, and cost-effectiveness, continue glucose monitoring could be the ideal diagnostic tool for the patient with diabetes on hemodialysis.
Collapse
Affiliation(s)
- Maurizio Gallieni
- Department of Biomedical and Clinical Sciences "Luigi Sacco", Università Di Milano, Milano, Italy.
- Nephrology and Dialysis Unit, ASST Fatebenefratelli Sacco, Milano, Italy.
| | - Cristina De Salvo
- Nephrology and Dialysis Unit, ASST Fatebenefratelli Sacco, Milano, Italy
| | | | - Antonio Rossi
- Division of Endocrinology, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Francesca D'Addio
- International Center for T1D, Pediatric Clinical Research Center Romeo Ed Enrica Invernizzi, Department of Biomedical and Clinical Sciences "L. Sacco", Università Di Milano, Milan, Italy
| | - Ida Pastore
- Division of Endocrinology, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Gianmarco Sabiu
- Nephrology and Dialysis Unit, ASST Fatebenefratelli Sacco, Milano, Italy
| | - Roberta Miglio
- Nephrology and Dialysis Unit, ASST Fatebenefratelli Sacco, Milano, Italy
| | - Gian Vincenzo Zuccotti
- Pediatric Clinical Research Center Romeo Ed Enrica Invernizzi, Department of Biomedical and Clinical Sciences "L. Sacco", Università Di Milano and Pediatric Department, Buzzi Children's Hospital, Milan, Italy
| | - Paolo Fiorina
- Division of Endocrinology, ASST Fatebenefratelli-Sacco, Milan, Italy
- International Center for T1D, Pediatric Clinical Research Center Romeo Ed Enrica Invernizzi, Department of Biomedical and Clinical Sciences "L. Sacco", Università Di Milano, Milan, Italy
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
2
|
Zhang H, Pan D, Wu X, Su W, Tang X, Zhao D, Sun L, Song B, Bai X, Li X. Platelet Protease Activated Receptor 1 Is Involved in the Hemostatic Effect of 20( S)-Protopanaxadiol by Regulating Calcium Signaling. Front Pharmacol 2020; 11:549150. [PMID: 33041793 PMCID: PMC7530267 DOI: 10.3389/fphar.2020.549150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 08/31/2020] [Indexed: 12/15/2022] Open
Abstract
Panax notoginseng (Burk.) F.H. Chen has long been used to stop bleeding for hundreds of years in China. At present, only dencichine, notoginsenoside Ft1, and 20(S)-protopanaxadiol (PPD) showed hemostatic effect. However, the molecular mechanism of PPD on the platelet aggragetion needs to be further investigated. The study aims to evaluate the hemostatic effect of PPD and reveal its interacting targets using a series of experiments. In this study, the bleeding time was measured in mouse tail amputation and liver scratch models to evaluate hemostatic effect of PPD. The routine blood and plasma coagulation parameters in NS, HC, and PPD (2, 4, and 8 mg/kg) groups were measured using a blood analyzer. Platelet aggregation rate and ATP release were analyzed by a platelet aggregometer. Subsequently, the degranulation marker CD62P and PAC-1, and the concentrations of cytosolic Ca2+ ([Ca2+]i), cAMP, cGMP, and PAC-1 expressions were also assessed. We found that PPD shorted the bleeding time on the mouse tail amputation and liver scratch models and mainly increased blood platelet count in the rats after subcutaneous injection for 4 h. Meanwhile, PPD decreased APTT, increased FIB content, and directly induced platelet aggregation in vitro. In the absence of Ca2+, PPD induced the increase of [Ca2+]i and slightly increased the levels of CD62P and PAC-1. After the addition of 1 mM Ca2+, PPD treatment markedly promoted platelet activation by promoting ATP level, releasing CD62P and increasing PAC-1 binding in washed platelets. Excitingly, PPD-induced changes including platelet aggregation, decreased cAMP content, and the increases of CD62P and PAC-1 were significantly reversed by protease-activated receptor 1 (PAR-1) antagonist, vorapaxar, which showed similar function as thrombin. In addition, molecular docking analysis and ELISA assay demonstrated that PPD had a promising docking score with -6.6 kcal/mol and increased PAR-1 expression in human platelets, which indicated that PAR-1 is involved in PPD-induced platelet aggregation by regulating calcium signaling. Collectively, our study could provide the new insights of PPD as an essential hemostatic ingredient in Panax notoginseng for the treatment of hemorrhagic disease.
Collapse
Affiliation(s)
- He Zhang
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Daian Pan
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Xingquan Wu
- Department of Tuina, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Wenjie Su
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Xiaolei Tang
- College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Daqing Zhao
- Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of BioMacromolecules of Chinese Medicine, Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| | - Liwei Sun
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Bailin Song
- Department of Tuina, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China.,College of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Xueyuan Bai
- Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of BioMacromolecules of Chinese Medicine, Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| | - Xiangyan Li
- Key Laboratory of Active Substances and Biological Mechanisms of Ginseng Efficacy, Ministry of Education, Jilin Provincial Key Laboratory of BioMacromolecules of Chinese Medicine, Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun, China
| |
Collapse
|
3
|
Garbossa SG, Folli F. Vitamin D, sub-inflammation and insulin resistance. A window on a potential role for the interaction between bone and glucose metabolism. Rev Endocr Metab Disord 2017; 18:243-258. [PMID: 28409320 DOI: 10.1007/s11154-017-9423-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vitamin D is a key hormone involved in the regulation of calcium/phosphorous balance and recently it has been implicated in the pathogenesis of sub-inflammation, insulin resistance and obesity. The two main forms of vitamin D are cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2): the active form (1,25-dihydroxyvitamin D) is the result of two hydroxylations that take place in liver, kidney, pancreas and immune cells. Vitamin D increases the production of some anti-inflammatory cytokines and reduces the release of some pro-inflammatory cytokines. Low levels of Vitamin D are also associated with an up-regulation of TLRs expression and a pro-inflammatory state. Regardless of the effect on inflammation, Vitamin D seems to directly increase insulin sensitivity and secretion, through different mechanisms. Considering the importance of low grade chronic inflammation in metabolic syndrome, obesity and diabetes, many authors hypothesized the involvement of this nutrient/hormone in the pathogenesis of these diseases. Vitamin D status could alter the balance between pro and anti-inflammatory cytokines and thus affect insulin action, lipid metabolism and adipose tissue function and structure. Numerous studies have shown that Vitamin D concentrations are inversely associated with pro-inflammatory markers, insulin resistance, glucose intolerance and obesity. Interestingly, some longitudinal trials suggested also an inverse association between vitamin D status and incident type 2 diabetes mellitus. However, vitamin D supplementation in humans showed controversial effects: with some studies demonstrating improvements in insulin sensitivity, glucose and lipid metabolism while others showing no beneficial effect on glycemic control and on inflammation. In conclusion, although the evidences of a significant role of Vitamin D on inflammation, insulin resistance and insulin secretion in the pathogenesis of obesity, metabolic syndrome and type 2 diabetes, its potential function in treatment and prevention of type 2 diabetes mellitus is unclear. Encouraging results have emerged from Vitamin D supplementation trials on patients at risk of developing diabetes and further studies are needed to fully explore and understand its clinical applications.
Collapse
Affiliation(s)
- Stefania Giuliana Garbossa
- Department of Internal Medicine, Azienda Socio Sanitaria Territoriale Santi Paolo e Carlo, Ospedale San Paolo, Via A. Di Rudini 8, Milan, 20142, Italy
- Program in Nutritional Science, Universitá degli Studi di Milano, Milan, Italy
| | - Franco Folli
- Department of Internal Medicine, Azienda Socio Sanitaria Territoriale Santi Paolo e Carlo, Ospedale San Paolo, Via A. Di Rudini 8, Milan, 20142, Italy.
- Endocrinology and Metabolism, Department of Health Science, Universitá degli Studi di Milano, San Paolo Hospital, Room #737, Via A. Di Rudiní 8, 20142, Milan, Italy.
- Department of Medicine, Diabetes Division, University of Texas Health System, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA.
| |
Collapse
|
4
|
Rein P, Saely CH, Silbernagel G, Vonbank A, Mathies R, Drexel H, Baumgartner I. Systemic inflammation is higher in peripheral artery disease than in stable coronary artery disease. Atherosclerosis 2015; 239:299-303. [DOI: 10.1016/j.atherosclerosis.2015.01.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 01/08/2015] [Accepted: 01/14/2015] [Indexed: 12/01/2022]
|
5
|
Barbieri M, Rizzo M, Marfella R, Boccardi V, Esposito A, Pansini A, Paolisso G. Decreased carotid atherosclerotic process by control of daily acute glucose fluctuations in diabetic patients treated by DPP-IV inhibitors. Atherosclerosis 2013; 227:349-54. [DOI: 10.1016/j.atherosclerosis.2012.12.018] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 12/12/2012] [Accepted: 12/13/2012] [Indexed: 01/08/2023]
|
6
|
Braun OO, Jagroop A, Wang L, Mikhailidis DP, Burnstock G, Erlinge D. Increased platelet purinergic sensitivity in peripheral arterial disease--a pilot study. Platelets 2005; 16:261-7. [PMID: 16011976 DOI: 10.1080/09537100400020203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Peripheral arterial disease (PAD) is associated with platelet hyperaggregability as well as an increase in morbidity and mortality from myocardial infarction (MI) and stroke. Purinergic signaling has been shown, both experimentally and clinically, to play an important role in the activation of platelets. Platelets express three different purinergic receptors: P2Y1, P2Y12 and P2X1. We assessed the hypothesis that the hyperaggregability associated with PAD is partly due to an increased P2 receptor expression at the transcriptional and/or translational level. Patients with PAD (n=8) and controls (n=8) were studied. Using a high-resolution channelyzer, platelet shape change (PSC) was assessed by measuring the median platelet volume (MPV). The fall in free platelet count following the addition of ADP was also assessed. Real-time PCR was used to quantify the mRNA expression and Western blots to quantify the protein expression of P2 receptors in platelets. The median (and range) fall in free platelet count after adding ADP was significantly (P=0.02) greater for patients [11% (5-24); n=8] than for controls [0.5% (0-10); n=8] despite using a lower concentration of ADP for the patient samples. The MPV did not differ significantly. The mRNA levels for the three P2 receptors were similar in PAD patients and controls. Western blot detected no significant differences in protein expression between these groups. Thus, platelets from PAD patients show an increased activation after stimulation with ADP (even though all patients were on aspirin). This hyperactivity was neither due to an obvious up-regulation of the mRNA levels nor to altered protein levels of P2 receptors in the platelets. It is suggested that the increased sensitivity to ADP in PAD is caused by post-receptor mechanisms.
Collapse
Affiliation(s)
- Oscar O Braun
- Department of Cardiology, Lund University Hospital, Lund, Sweden
| | | | | | | | | | | |
Collapse
|
7
|
Fiorina P, Folli F, Ferrero E, Orsenigo E, Finzi G, Mazzolari G, Placidi C, Perego L, La Rosa S, Melandri M, Monti L, Capella C, D'Angelo A, Staudacher C, Secchi A. Morphological and functional differences in haemostatic axis between kidney transplanted and end-stage renal disease patients. Transpl Int 2005; 18:1036-47. [PMID: 16101724 DOI: 10.1111/j.1432-2277.2005.00173.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
End-stage renal disease (ESRD) is characterized by several atherothrombotic abnormalities, and kidney transplant seems to improve most of them. However, because it is not clear which mechanism is responsible for such improvement, our purpose was to clarify that point.We conducted a cross sectional study involving 30 ESRD patients, 30 ESRD kidney-transplanted patients (Ktx) and 30 healthy controls (C) to evaluate platelet morphology and function, atherothrombotic profile, endothelial abnormalities and cytokine levels involved in the insulin resistance/endothelial dysfunction. (i) Platelet morphology: The ESRD group showed platelet size similar to the other two groups (ESRD=3518x10(3)+/-549x10(3) nm2, C=3075x10(3)+/-197x10(3) nm2, Ktx=2862x10(3)+/-205x10(3) nm2) with similar platelet granules and number. (ii) Platelet surface glycoprotein: The CD41 and P-Selectin were similar between groups. (iii) Platelet intracellular calcium: Resting intracellular calcium was statistically higher in ESRD compared to the C group (ESRD=182.1+/-34.5, Ktx=126.7+/-14.1, C=72.0+/-11.0 nM, P<0.01). (iv) Hypercoagulability markers and natural anticoagulants: The Ktx and ESRD groups showed higher levels of hypercoagulability markers compared to the C group. A reduction in antithrombin activity was evident in ESRD compared to the Ktx group (P=0.03). (v) Endothelial morphology: The ESRD group showed a thickened vessel basal membrane compared to the Ktx and C groups with more endothelial sufference. (vi) Insulin resistance and pro-inflammatory cytokine profile: The ESRD showed a higher homeostasis model assessment provided equations for estimating insulin resistance (HOMA-IR) compared to the Ktx and C groups (ESRD=2.6+/-0.3, Ktx=1.8+/-0.2, C=1.1+/-0.1, P=0.005) and increased soluble tumor neurosis factor alpha (sTNFalpha) (P<0.05) and soluble vascular cell adhesion molecule (sVCAM) levels (P<0.01). Positive correlations were evident among HOMA-IR and sTNFalpha (P<0.001) and sVCAM (P=0.01), respectively. In a small subgroup of ESRD who underwent Ktx (five pts), our findings were confirmed at 1 year of follow-up, suggesting an improvement of almost haemostatic abnormalities. Kidney transplant is associated with a better atherothrombotic profile in ESRD, platelet intracellular calcium and cytokines seem to be most influenced by the transplant, while most morphological abnormalities are retained.
Collapse
Affiliation(s)
- Paolo Fiorina
- Department of Internal Medicine, San Raffaele Scientific Institute, Milan, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Fiorina P, Folli F, D'Angelo A, Finzi G, Pellegatta F, Guzzi V, Fedeli C, Della Valle P, Usellini L, Placidi C, Bifari F, Belloni D, Ferrero E, Capella C, Secchi A. Normalization of multiple hemostatic abnormalities in uremic type 1 diabetic patients after kidney-pancreas transplantation. Diabetes 2004; 53:2291-300. [PMID: 15331538 DOI: 10.2337/diabetes.53.9.2291] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To evaluate the effects of kidney-pancreas transplantation on hemostatic abnormalities in uremic type 1 diabetic patients, we conducted a cross-sectional study involving 12 type 1 diabetic patients, 30 uremic type 1 diabetic patients, 27 uremic type 1 diabetic patients who had a kidney-pancreas transplant, 12 uremic type 1 diabetic patients who had a kidney-alone transplant, and 13 healthy control subjects. We evaluated platelet and clotting system. Platelets in the group of uremic type 1 diabetic patients were significantly larger than platelets in the other groups. Resting calcium levels were significantly higher in the uremic type 1 diabetic patients and uremic type 1 diabetic patients who had a kidney-alone transplant than in the type 1 diabetic patients who had a kidney-pancreas transplant and control subjects. CD41 expression was significantly reduced in platelets from the uremic type 1 diabetic patients compared with the other groups. Levels of hypercoagulability markers in the type 1 diabetic patients who had a kidney-pancreas transplant and, to a lesser extent, the uremic type 1 diabetic patients who had a kidney-alone transplant but not the uremic type 1 diabetic patients were similar to those of the control subjects. A reduction in natural anticoagulants was evident in the uremic type 1 diabetic patients, whereas near-normal values were observed in the type 1 diabetic patients who had a kidney-pancreas transplant and uremic type 1 diabetic patients who had a kidney-alone transplant. Hemostatic abnormalities were not observed in type 1 diabetic patients who had a kidney-pancreas transplant. This finding might explain the lower cardiovascular death rate observed in type 1 diabetic patients who had a kidney-pancreas transplant compared with uremic type 1 diabetic patients who had a kidney-alone transplant or uremic type 1 diabetic patients.
Collapse
Affiliation(s)
- Paolo Fiorina
- Internal Medicine, San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milano, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Abstract
Platelets are small, non-homogenous cells with distinctive surface features important to their essential role in hemostasis. The surface membrane is dynamic, and changes remarkably in lipid asymmetry and receptor expression on triggering of the activation process. There are also extensive and rapid intracellular changes in platelets as a result of biochemical activation through calcium fluxes, phospholipase activity, kinase activity, and phosphorylation mechanisms that lead to release of storage granule contents and generation of fast-acting prostaglandins, all in a matter of seconds after stimulation with a strong agonist. These characteristics make the platelet an interesting but difficult cell to study, and the explosion of knowledge over the last two decades has been fueled in large part by the application of flow cytometry techniques. Clinical applications of flow cytometry analysis of platelets have been pursued in individual specialized medical centers, but have not found widespread practice in clinical laboratories, mostly because of difficulties in standardization of techniques and the inherent biovariability in comparing normal to abnormal platelets. Despite these hurdles, it seems certain that flow cytometry analysis of platelets in pathological states will continue to evolve into more practical and robust procedures that will eventually become standard hematologic assays rather than specialized research tools.
Collapse
Affiliation(s)
- Darren H M Hickerson
- Department of Pathology and Laboratory Medicine, 241 Life Sciences Building, Brody School of Medicine, East Carolina University, Greenville, NC 27858, USA
| | | |
Collapse
|
10
|
Feijge MA, van Pampus EC, Lacabaratz-Porret C, Hamulyàk K, Levy-Toledano S, Enouf J, Heemskerk JW. Inter-individual variability in Ca2+ signalling in platelets from healthy volunteers: effects of aspirin and relationship with expression of endomembrane Ca2+-ATPases. Br J Haematol 1998; 102:850-9. [PMID: 9722316 DOI: 10.1046/j.1365-2141.1998.00844.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Increased Ca2+ signal generation may lead to hyperactivity of platelets and contribute to thrombotic complications. Using fura-2-loaded platelets from 51 healthy volunteers, high variability was detected in the Ca2+ responses evoked by the receptor agonists, thrombin and collagen, and the inhibitor of sarco/endoplasmic reticulum Ca2+-ATPases (SERCA), thapsigargin (Tg). Oral intake of 500mg aspirin reduced the magnitude of the Ca2+ responses, and lowered the intra-individual coefficients of variance of the responses by 50%. However, the corresponding inter-individual variance coefficients were only a little influenced by aspirin intake, pointing to subject-dependent factors in Ca2+ handling that are unrelated to thromboxane formation. With each agonist, 6-9% of the subjects had platelets with relatively high Ca2+ responses (> mean + SD) both before and after aspirin intake. In 90% (9/10) of these cases the high responsiveness was confirmed in platelets obtained 6-12 months later. The Tg- but not thrombin-induced Ca2+ responses correlated inversely with the expression levels of SERCA PL/IM 430 (SERCA-3b) in platelets. After aspirin intake, the Ca2+ responses with collagen but not thrombin correlated inversely with SERCA-2b expression. These results suggest that, in the absence of potentiating effects of thromboxane, (i) the amount of PL/IM 430-recognizable SERCA may control the Ca2+ signal when SERCA-2b is specifically inhibited (with Tg), and (ii) the expression of SERCA-2b determine the collagen- but not the thrombin-evoked Ca2+ signal. Accordingly, limited Ca2+-pumping activity by low expression of one of the SERCA isoforms is likely to be one of the factors resulting in increased platelet activity towards collagen or thapsigargin but not thrombin.
Collapse
Affiliation(s)
- M A Feijge
- Department of Human Biology/Biochemistry, University of Maastricht, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
11
|
Fowler CJ, Tiger G. Calibration of Fura-2 signals introduces errors into measurement of thrombin-stimulated calcium mobilisation in human platelets. Clin Chim Acta 1997; 265:247-61. [PMID: 9385466 DOI: 10.1016/s0009-8981(97)00139-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The intracellular calcium indicator dye Fura-2 has been widely used for the study of human platelet thrombin receptor-mediated calcium mobilisation in disease states. In general, authors (a) use a Fura-2/AM concentration of 2-3 mumol/l and (b) calibrate fluorescence signals on the basis of maximum and minimum ratios of fluorescence (Rmax and Rmin) and the ratio of the calcium-free and calcium-bound fluorescence at an excitation wavelength of 380 nm ("C2/B2"). In the present study, it is found (a) that a greater peak response to thrombin is seen when 1 mumol/l Fura-2/AM rather than 2 or 3 mumol/l is used; and (b) that calibration leads to a poorer test-retest reliability and in general a greater variability of the obtained calcium signal than when the simple measurement of the 340 nm/380 nm fluorescence ratio is used. It is suggested that this poor variability is due to the presence of an extracellular factor that can quench the Fura-2 signal once the platelets have been permeabilised by detergent treatment. Consistent with this, addition of bovine serum albumin to the assay medium has no significant effect on the fluorescence ratio response to thrombin, but greatly increases the observed calibrated calcium signal.
Collapse
Affiliation(s)
- C J Fowler
- Department of Pharmacology, Umeå University, Sweden.
| | | |
Collapse
|