Platelets are rich in growth factors that may contribute to an accelerated tissue regeneration process. The therapeutic osteogenic effect of local platelet administration probably depends on the ...amount of growth factors delivered within. To improve platelet-derived factor preparations, the platelets have to be concentrated without loss of the granular growth factor load. An autologous procedure according to the Good Manufacture Practice (GMP) guidelines to prepare a high concentrate from platelet-rich plasma (cPRP) for clinical application in bone regeneration is presented. Platelet-rich plasma (PRP) was generated from the centrifugation supernatant of 250ml anticoagulated autologous blood. The PRP was then further centrifuged at the day of operation to generate concentrated PRP (cPRP) in 8ml plasma. The data from 34 patients (9m, 25f), ageing from 21 to 71 years (median 50.4) were evaluated. Both, the platelet counts as well as the TGF-β1 concentrations in the cPRP were found to be 12-fold increased compared to the PRP values. Overall, a 17-fold increase in platelet concentrations was achieved compared to the patients' whole bloods and platelet counts correlated with increased levels of TGF-β1 within the cPRP. These results give rise to quality control specifications for a safe and cost effective preparation of cPRP. The method has proven to be suitable for blood services to support the needs for treatment in oral and maxillofacial surgery.
Mesenchymal stromal cells (MSCs) are promising cell therapy candidates. Clinical application is considered safe. However, minor side effects have included thromboembolism and instant blood-mediated ...inflammatory reactions suggesting an effect of MSC infusion on hemostasis. Previous studies focusing on plasmatic coagulation as a secondary hemostasis step detected both procoagulatory and anticoagulatory activities of MSCs. We now focus on primary hemostasis and analyzed whether MSCs can promote or inhibit platelet activation.
Effects of MSCs and MSC supernatant on platelet activation and function were studied using flow cytometry and further platelet function analyses. MSCs from bone marrow (BM), lipoaspirate (LA) and cord blood (CB) were compared to human umbilical vein endothelial cells or HeLa tumor cells as inhibitory or activating cells, respectively.
BM-MSCs and LA-MSCs inhibited activation and aggregation of stimulated platelets independent of the agonist used. This inhibitory effect was confirmed in diagnostic point-of-care platelet function analyses in platelet-rich plasma and whole blood. Using inhibitors of the CD39-CD73-adenosine axis, we showed that adenosine produced by CD73 ectonucleotidase activity was largely responsible for the LA-MSC and BM-MSC platelet inhibitory action. With CB-MSCs, batch-dependent responses were obvious, with some batches exerting inhibition and others lacking this effect.
Studies focusing on plasmatic coagulation suggested both procoagulatory and anticoagulatory activities of MSCs. We now show that MSCs can, dependent on their tissue origin, inhibit platelet activation involving adenosine converted from adenosine monophosphate by CD73 ectonucleotidase activity. These data may have strong implications for safety and risk/benefit assessment regarding MSCs from different tissue sources and may help to explain the tissue protective mode of action of MSCs. The adenosinergic pathway emerges as a key mechanism by which MSCs exert hemostatic and immunomodulatory functions.
Background and Objectives Previous studies have shown substantial geographical variation in blood donation within developed countries. To understand this issue better, we identified community ...characteristics associated with blood donor rates in German municipalities in an ecological analysis.
Materials and Methods We calculated an aggregated rate of voluntary blood donors from each of 1533 municipalities in south‐west Germany in 2007 from a database of the German Red Cross Blood Service. A multiple linear regression model estimated the association between the municipality‐specific donor rate and several community characteristics. Finally, a spatial lag regression model was used to control for spatial autocorrelation that occurs when neighbouring units are related to each other.
Results The spatial lag regression model showed that a relatively larger population, a higher percentage of inhabitants older than 30 years, a higher percentage of non‐German citizens and a higher percentage of unemployed persons were associated with lower municipality‐specific donor rates. Conversely, a higher donor rate was correlated with higher voter turnout, a higher percentage of inhabitants between 18 and 24 years and more frequent mobile donation sites.
Conclusions Blood donation appears to be a highly clustered regional phenomenon, suggesting the need for regionally targeted recruiting efforts and careful consideration of the value of mobile donation sites. Our model further suggests that municipalities with a decreasing percentage of 18‐ to 24‐year‐olds and an increasing percentage of older inhabitants may experience substantial declines in future blood donations.
For the first time since the reunification of Germany, right-wing activists
and politicians have attempted to take over a university city, i.e. a place
where the highly educated, creative, ...cosmopolitan, innovation-oriented
groups should be more likely to question irrational populism than elsewhere.
An internal organizational problem – in this case: the renaming of the
University of Greifswald – which normally should be solved with on-board
resources, was shifted to a regional political level as a dispute over Ernst
Moritz Arndt. Arndt was one of the most aggressive nationalists in German
history, whose name was given to the university under fascist rule in 1933.
The dispute was emotionalized by demonstrations and letters to the editor of
the regional newspaper, taken up by groups and parties predominantly from
the right-wing spectrum. It was brought into a populist form, and pushed
with high journalistic effort into the regional public sphere as a
Pomeranian identity crisis. In spite of the enormous pressure from outside
and the numerous attempts at intimidation, it is admirable that the
University Senate members decided to discard the name of Arndt – 63 years
after the end of World War II. Although the result of the renaming was noted nationwide, its dramatic circumstances and background were not presented. However, this would have been necessary in order to show how strong right-wing radicalism already is in some regions, by which coalitions it is further enhanced, how strongly it is favoured by the spatial over-centralisation of state institutions, and what a university has to afford in order to assert itself successfully in such an environment.
Background and Objectives Mirasol® pathogen reduction technology (PRT) for platelet concentrates uses riboflavin and ultraviolet light. Previously, we described increased metabolism and activation ...for PRT platelets stored in 100% plasma. To improve platelet quality, we resuspended platelets in a mixture of plasma and platelet additive solution (PAS).
Materials and Methods Single‐donor platelets were resuspended in plasma and split into an untreated control and a PRT‐treated single product. One hundred and fifty millilitre PAS (SSP+) was added to both. Over 7 days, we assayed pH, glucose consumption‐, lactate production rate and CD62p with and without TRAP.
Results On day 5, PRT units showed a significantly lower pH (7·087 ± 0·105 vs. 7·288 ± 0·200) accompanied by a higher lactate production (0·104 ± 0014 vs. 0·063 ± 0·017 mmol/1012/h) and glucose consumption rate (0·039 ± 0005 vs. 0·028 ± 0·009 mmol/1012 platelets/h). CD62p expression was higher in treated units (44·5 ± 13·0 vs. 16·5 ± 7·6%).
Conclusion In comparison to PRT platelets resuspended in 100% plasma, a mixture of plasma and PAS improves pH and platelet metabolism but not platelet activation. Prolonged shelf‐life for up to 7 days may be possible.
BACKGROUND: Nonhemolytic transfusion reactions (NHTRs) frequently occur after platelet transfusions. White cell (WBC)‐derived inflammatory cytokines can cause these reactions, but they are rarely ...found in WBC‐poor platelet preparations. Transfusion reactions were investigated with regard to the residual WBC content in the stored platelet concentrate in two consecutive study periods.
STUDY DESIGN AND METHODS: In the first study period, platelet concentrates were WBC‐reduced by bedside filtration. In the second period, all platelet concentrates were filtered before storage. Recipients who experienced transfusion reactions were examined with regard to their main clinical symptoms during and after transfusion. In the supernatant of the involved platelet concentrates, concentrations of interleukin (IL)‐1β, IL‐6, IL‐8, tumor necrosis factor (TNF)α, macrophage inflammatory protein 1α, and RANTES were analyzed.
RESULTS: The incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage WBC filtration (1.63% and 1.56%; p = 0.84). In both periods, NHTRs were predominantly of allergic origin. Inflammatory mediators IL‐1β, IL‐6, IL‐8, and TNFα were detectable in only a minority of platelet components involved in NHTRs. Platelet concentrates involved in allergic reactions contained high concentrations of RANTES (668 ± 223 ng/mL).
CONCLUSIONS: Prestorage WBC filtration did not reduce the incidence of these reactions, and inflammatory cytokines were of minor relevance. The proinflammatory platelet‐derived chemokine RANTES, which accumulates even in WBC‐reduced platelet concentrates, was associated with allergic transfusion reactions. Platelet‐derived mediators may be a key to understanding NHTRs.
Chronic inflammation is a major contributing factor to atherosclerosis and various markers of inflammation, fibrinolysis and coagulation are upregulated in patients with established atherosclerotic ...disease. The aim of this study was to investigate the direct and short-term effects of inflammation on platelet and monocyte activation with an in vivo model of endotoxemia in healthy volunteers.
In this study, 13 healthy male subjects with a mean age of 29.5+/-5.4 years received intravenous administration of lipopolysaccharide (LPS; 20 IU/kg IV). The kinetics of CD40-ligand and CD62P expression on platelets, tissue-factor binding on monocytes and platelet-monocyte aggregates were measured by whole blood flow cytometry at baseline and at 1, 2, 4, 6 and 24 hours after LPS administration. Plasma levels of soluble CD40-ligand were measured with an ELISA over the same time course. Platelet-monocyte aggregates, tissue-factor binding on monocytes and surface expression of platelet CD40L significantly increased in experimental endotoxemia in vivo, reaching peak values 1 hour after LPS administration. All values returned to baseline after 24 hours. Surface expression of CD62P on platelets and plasma levels of sCD40L did not change significantly in response to LPS.
In vivo administration of endotoxin leads to an activation of platelets and monocytes with an upregulation of proatherogenic CD40L on platelets. These findings underpin the role of inflammation in early atherogenesis through platelet and monocyte activation in an in vivo model.
Interleukin-12 (IL-12), a heterodimeric cytokine, is important in the generation of a Th1-biased immune response. Several polymorphisms have been described in IL12B, the gene encoding the p40 subunit ...of IL-12. A bi-allelic polymorphism within the IL12B promoter region has been reported to show association with diseases as diverse as severe childhood asthma and fatal cerebral malaria. In order to define the molecular basis for these disease associations, we investigated the secretion of IL-12 by human monocyte-derived dendritic cells. Homozygotes for the IL12B promoter polymorphism showed a 10-fold difference in median p70 secretion in response to CD40 ligation. Remarkably, this difference resulted from the inability of most allele 1 homozygotes to secrete heterodimeric IL-12. In contrast, most of the donors homozygous for allele 2 had detectable secretion. These findings are important for the understanding of the highly complex regulation of IL-12 secretion, and its consequent impact on disease susceptibility, in humans.
Background Within the coming decades, a steadily growing demand for blood products will face a shrinking blood donor population in many countries. After increasing the donor age of repeat donors for ...whole blood donation (WB) from 68 to 70 years in 2009 in our Blood Service, we investigated whether this is sufficient as a safe and effective strategy to sustain future blood supply.
Materials and Methods Between 1 March 2009 and 28 February 2011, WB donations from donors aged between 69 and 70 and their proportion of total donations in 2010 were determined. We analysed adverse reaction rates in donors with respect to sex and age and calculated mean annual donation frequencies.
Results Of all invited donors, 32·5% responded and contributed 0·98% (men) and 0·56% (women) to all WB units collected in 2010. The overall and systemic adverse reaction rate per 1·000 WB donations declined by age men: 1·10 (95%CI: 0·84–1·35) vs. 0 (0–0·8), P < 0·0001; 0·99 (0·75–1·23) vs. 0 (0–0·8), P < 0·0001 and women: 1·80 (1·46–2·14) vs. 1·12 (0·1–2·66), P < 0·0001; 1·47 (1·17–1·78) vs. 1·12 (−0·43–2·66), P = 0·0004. Mean donation frequencies were strongly correlated with increasing age (men: r = 0·953, P < 0·0001; women: r = 0·913, P < 0·0001) with peak values for 70‐year‐old male: 2·53 ± 1·37 vs. 1·79 ± 1·05, P < 0·0001 and female donors: 2·15 ± 1·06 vs. 1·52 ± 0·78, P < 0·0001.
Conclusions Elderly donors have very low adverse reaction frequencies and are highly committed to donate blood. Thus, we consider donations from repeat donors aged 69–70 safe and suggest it a powerful short‐ to midterm strategy to, at least partially, overcome the challenges of the demographic change.
PDF
