Deletion of protein kinase Cε in mice has limited effects on liver metabolite levels but alters fasting ketogenesis and gluconeogenesis

AIMS/HYPOTHESIS

Protein kinase Cε (PKCε) is emerging as a key mediator of lipid-induced insulin resistance in liver and hepatic lipid metabolism itself. We investigated whether PKCε plays a role in other metabolic processes, to further examine its suitability as a therapeutic target.

METHODS

We measured amino acid, organic acid and sugar levels by liquid and gas chromatography-mass spectrometry of liver extracts from chow and fat-fed wild-type (WT) and PKCε-deficient (Prkce(-/-)) mice. Fed and fasting glucose, ketone and fatty acid levels were measured in blood. Triacylglycerol levels and gluconeogenic and ketogenic enzyme expression were measured in liver. The effect of fasting on epididymal fat pad mass was also determined.

RESULTS

Metabolomic analysis indicated that the short-term high-fat diet affected over 20 compounds, including a 50% reduction in the glucogenic amino acid alanine. Prkce deletion resulted only in a reduction of 4-hydroxyproline and aspartate and an increase in glutamate. However, upon fasting, Prkce(-/-) mice were better able to maintain blood glucose levels and also exhibited lower levels of the ketone β-hydroxybutyrate compared with WT mice. Upon fasting, Prkce deletion also resulted in lower liver and plasma lipids and a smaller reduction in fat pad mass.

CONCLUSIONS/INTERPRETATION

Metabolomic analysis provided new insights into the effects of a high-fat diet on liver metabolite levels. Glucose homeostasis under fasting conditions is improved in Prkce(-/-) mice, which, in turn, may reduce the mobilisation of lipid from adipose tissue, reducing the availability of ketogenic substrate in the liver. Together with the protection against fat-diet-induced glucose intolerance previously observed in the fed state, these findings indicate PKCε as a unique therapeutic target for the improvement of glucose homeostasis.

[Coagulation and cirrhosis: new insight]

The liver plays a key role in coagulation as all clotting factors except for factor VIII are synthetized by hepatocytes. In cirrhotic patients, there is a decrease of clotting factors and a thrombocytopenia. Those parameters usually modify routine coagulation tests and may suggest that cirrhotic patients are at a higher risk of bleeding. However, studies have shown that these patients are rather at risk for thrombosis. The reason is a concomitant decrease of coagulation inhibitors factors that is not detected in routine laboratory coagulation tests. The coagulation system in cirrhotic patient is a balance of pro and anti-coagulants. This balance may be affected by co-factors such as renal failure or infection. Artificial correction of laboratory values by transfusion of blood products may be rather deleterious (e.g. volume overload, TRALI).

von Willebrand factor: more than a regulator of hemostasis and thrombosis

von Willebrand factor (vWF) was first identified as an adhesive glycoprotein involved in hemostasis by Zimmermann in 1971. Since then, vWF has been shown to play a vital role in platelet adhesion, platelet binding to collagen and factor VIII protection. Recent studies have implicated vWF as a regulator of angiogenesis, smooth muscle cell proliferation, tumor cell metastasis and crosstalk in the immune system. In this review, we will discuss the aspects of vWF structure that facilitate its biological effects and speculate on its newly discovered and hypothesized roles in the pathogenesis of several diseases.

Gap junctions and connexin hemichannels underpin hemostasis and thrombosis

BACKGROUND

Connexins are a widespread family of membrane proteins that assemble into hexameric hemichannels, also known as connexons. Connexons regulate membrane permeability in individual cells or couple between adjacent cells to form gap junctions and thereby provide a pathway for regulated intercellular communication. We have examined the role of connexins in platelets, blood cells that circulate in isolation but on tissue injury adhere to each other and the vessel wall to prevent blood loss and to facilitate wound repair.

METHODS AND RESULTS

We report the presence of connexins in platelets, notably connexin37, and that the formation of gap junctions within platelet thrombi is required for the control of clot retraction. Inhibition of connexin function modulated a range of platelet functional responses before platelet-platelet contact and reduced laser-induced thrombosis in vivo in mice. Deletion of the Cx37 gene (Gja4) in transgenic mice reduced platelet aggregation, fibrinogen binding, granule secretion, and clot retraction, indicating an important role for connexin37 hemichannels and gap junctions in platelet thrombus function.

CONCLUSIONS

Together, these data demonstrate that platelet gap junctions and hemichannels underpin the control of hemostasis and thrombosis and represent potential therapeutic targets.

Subclinical hypothyroidism and homeostatic disturbances: case report and literature review

Abnormalities of coagulation have been reported in patients with thyroid dysfunction, although there is no clear information to explain the mechanism behind such irregularities. We are presenting a case of subclinical hypothyroidism that came with coagulation disturbance (hypocoagulation). Her symptoms resolved with leothyroxin in 4 weeks. Further studies are needed to clear the pathogenesis of the coagulation disturbance in such setting. The article also outlines some patents on hypothyroidism and hyperthyroidism.

[Haemostasis disturbances as the component of the surgical stress-response and possibilities of their correction]

OBJECTIVE

An estimation of haemostasis parameters in the major abdominal surgery in comparision with surgical stress-response markers depending on anaesthesia and analgesia technique.

METHODS

120 patients scheduled to undergo elective low-abdominal surgery were allocated to receive either general anaesthesia (n=40) or combined (general + epidural (n=40) or general + spinal (n=40)) anaesthesia. Postoperative analgesia, glucose, cortisol and cytokine levels, as well as coagulation, fibrinolysis, thrombocyte aggregation parameters were estimated.

RESULTS

The epidural anaesthesia provided better postoperative analgesia. However both spinal and epidural anaesthesia show comparable correction of surgical stress-response markers. Also both types of regional anaesthesia reduced hypercoagulation expression and prevented fibrinolysis activation. This resulted in a reduction in the hemotransfusion frequency

CONCLUSION

Hemostasis changes can be considered as a component of the surgical stress-response. The role of intraoperative regional anaesthesia is much more significant, than postoperative analgesia.

[Hemostasis during MARS therapy and hemodiafitration in patiens with acute renal-hepatic failure]

OBJECTIVE

to study the dynamics of the haemostatic system, depending on coagulopathy type and efferent therapy method (HDF, MARS) in patiens with acute renal-hepatic failure. As a complex of intensive therapy, all the patients were trated extracorporeal techniques: HDF therapy in group I (n = 121) and MARS in group 1 (n = 62). Patients were aged from 18 to 67 years.

RESULTS AND DISCUSSION

MARS - is an effective therapy and has effects on haemostasis system: observed recovery of platelet-vascular disorders of coagulation and haemostasis. HDF is effective in patients with coagulation type of laboratory disseminated intravascular coagulation (DIC), and was dangerous in fibrinolytic DIC type because of haemostasis status decompensation risk.

P2Y(12) receptors in platelets and other hematopoietic and non-hematopoietic cells

The P2Y(12) receptor is a Gi-coupled ADP receptor first described in blood platelets where it plays a central role in the complex processes of activation and aggregation. Platelet granules store important amounts of ADP which are released upon stimulation by interaction of platelets with the damaged vessel wall. Therefore, the P2Y(12) receptor is a key player in primary hemostasis and in arterial thrombosis and is an established target of antithrombotic drugs like the thienopyridine compounds ticlopidine, clopidogrel, and prasugrel or the direct, reversible antagonists ticagrelor and cangrelor. Beyond the platelet physiology and pharmacology, recent studies have revealed the expression of the P2Y(12) receptor in other hematopoietic cells including leukocyte subtypes and microglia in the central nervous system as well as in vascular smooth muscle cells. These studies indicate putative roles of the P2Y(12) receptor in inflammatory states and diseases of the brain, lung, and blood vessels. The selective role of P2Y(12) among other P2 receptors as well as the possible impact of P2Y(12) targeting drugs in these processes remain to be evaluated.

On the integration of the baroreflex control mechanism in a heterogeneous model of the cardiovascular system

The aim of the present work is to describe the integration of a mathematical model for the baroreceptor reflex mechanism to provide regulatory action into a dimensionally heterogeneous (3D-1D-0D) closed-loop model of the cardiovascular system. Such heterogeneous model comprises a 1D description of the arterial tree, a 0D network for the venous, cardiac and pulmonary circulations and 3D patient-specific geometries for vascular districts of interest. Thus, the detailed topological description of the arterial network allows us to perform vasomotor control actions in a differentiated way, while gaining insight about the effects of the baroreflex regulation over hemodynamic quantities of interest throughout the entire network. Two examples of application are presented. Firstly, we simulate the hemorrhage in the abdominal aorta artery and analyze the action of the baroreflex over the system. Secondly, the self-regulated closed-loop model is applied to study the influence of the control action in the hemodynamic environment that determines the blood flow pattern in a cerebral aneurism in the presence of a regurgitating aortic valve.

[Dependence of haemostasis system response from initial blood coagulation activity under total joints replacement]

Effect of the initial state of the plasma hemostasis on the hemocoagulation changes after the total arthroplasty surgery was studied in 100 patients with osteoarthritis. Indicators of coagulation, fibrinolysis, and physiological anticoagulants were determined before and after completion of the surgery, at days 1, 3, 7, and 13-14 postoperatively. Increased coagulation activity befor surgery enhanced blood clotting within three days after the surgery. Enhanced consumption of physiological anticoagulants reduced the ability to recover their level a week after arthroplasty. The raised activity of the fibrinolysis inhibitor retained the effect during three postoperative days. Initial abnormalities in plasma hemostasis enhance blood coagulation dysfunction caused by surgical intervention on the large joints.

Clinical practice: the bleeding child. Part II: disorders of secondary hemostasis and fibrinolysis

Bleeding complications in children may be caused by disorders of secondary hemostasis or fibrinolysis. Characteristic features in medical history and physical examination, especially of hemophilia, are palpable deep hematomas, bleeding in joints and muscles, and recurrent bleedings. A detailed medical and family history combined with a thorough physical examination is essential to distinguish abnormal from normal bleeding and to decide whether it is necessary to perform diagnostic laboratory evaluation. Initial laboratory tests include prothrombin time and activated partial thromboplastin time. Knowledge of the classical coagulation cascade with its intrinsic, extrinsic, and common pathways, is useful to identify potential defects in the coagulation in order to decide which additional coagulation tests should be performed.

The multiple roles of tissue factor in wound healing

The procoagulant role of tissue factor (TF) is well recognized. The ability to form a hemostatic clot is essential to normal healing of an injury. However, TF also has additional activities as a regulator of cellular processes. Both by production of coagulant molecules that also have cytokine and growth factor-like activities, and by directly mediating cell signaling events, TF has the potential to influence the course and tempo of healing. The literature in this are remains somewhat sparse, but suggests that modulation of TF expression plays a role in modulating the host response to injury.

von Willebrand factor: an emerging target in stroke therapy

Thrombus formation is of paramount importance in the pathophysiology of acute ischemic stroke. Current antithrombotics used to treat or prevent cerebral ischemia are only moderately effective or bear an increased risk of severe bleeding. von Willebrand factor (VWF) has long been known to be a key player in thrombus formation at sites of vascular damage. While the association between VWF and coronary heart disease has been well studied, knowledge about the role of VWF in stroke is much more limited. However, in recent years, an increasing amount of clinical and preclinical evidence has revealed the critical involvement of VWF in stroke development. This review summarizes the latest insights into the pathophysiologic role of VWF-related processes in ischemic brain injury under experimental conditions and in humans. Potential clinical merits of novel inhibitors of VWF-mediated platelet adhesion and activation as powerful and safe tools to combat thromboembolic disorders including ischemic stroke are discussed. Preclinical and clinical evidence illustrates an important role of VWF in ischemic stroke, suggesting that VWF could become a promising target in stroke therapy.

Factor VII-activating protease promotes the proteolysis and inhibition of tissue factor pathway inhibitor

OBJECTIVE

Factor VII-activating protease (FSAP) activates both factor VII and pro-urokinase and inhibits platelet-derived growth factor-BB, thus regulating hemostasis- and remodeling-associated processes in the vasculature. A genetic variant of FSAP (Marburg I polymorphism) results in low enzymatic activity and is associated with an enhanced risk of carotid stenosis and stroke. We postulate that there are additional substrates for FSAP that will help to explain its role in vascular biology and have searched for such a substrate.

METHODS AND RESULTS

Using screening procedures to determine the influence of FSAP on various hemostasis-related processes on endothelial cells, we discovered that FSAP inhibited tissue factor pathway inhibitor (TFPI), a major anticoagulant secreted by these cells. Proteolytic degradation of TFPI by FSAP could also be demonstrated by Western blotting, and the exact cleavage sites were determined by N-terminal sequencing. The Marburg I variant of FSAP had a diminished ability to inhibit TFPI. A monoclonal antibody to FSAP that specifically inhibited FSAP binding to TFPI reversed the inhibitory effect of FSAP on TFPI.

CONCLUSIONS

The identification of TFPI as a sensitive substrate for FSAP increases our understanding of its role in regulating hemostasis and proliferative remodeling events in the vasculature.

[Peculiarities of hemostasis reactivity under stress load in persons with different degree of physical training]

Healthy young persons with different degrees of physical training have been impacted with exposure to a stress (a single physical exercise). It caused unidirectional hypercoagulative shifts and activation of anticoagulant and fibrinolytic blood systems. It was shown that changes of the untrained individuals' haemostatic parameters could be adjusted with adaptogen preliminary administration. The adaptogen administration in trained individuals resulted in disadaptive shifts in the haemostatic system. These contradictory changes indicate different levels of subject's adaptive potential.

Genetic regulation of inflammation-mediated activation of haemostasis: family-based approaches in population studies

Blood coagulation and inflammation play a key role in atherosclerosis and thrombosis. Candidate gene and genome wide association studies have identified potential specific genes that might have a causal role in these pathogenic processes. The analysis of quantitative traits is more powerful as they are closer to direct gene action than disease phenotypes. Thus linkage-based studies on extended families might be useful both to estimate the heritability and to map the genetic loci responsible for the regulation of the trait. Family-based studies may estimate high heritability for thrombosis and quantitative traits regarding both platelet aggregation and blood coagulation. Some specific loci relevant to thrombosis have been identified, with some of them showing a direct pleiotropic effect on the risk of thrombosis. Haemostasis factors can be activated by inflammatory stimuli. Fibrinogen level is genetically correlated with C-reactive protein levels with a link for both traits on chromosomes 12 and 21. Genes related to prostanoid biosynthesis, involved both in inflammation and thrombosis, show high heritability levels in both enzyme expression and prostanoid production. Considering that few large family-based linkage studies have as yet been performed on haemostasis and inflammation-related traits, additional studies are highly needed. We are performing a family-based linkage study on large pedigrees (750 subjects from 23 families with juvenile myocardial infarction and 31 control families), to identify genes responsible for quantitative traits involved in the pathway progressively going from inflammation to haemostasis, cell activation, thrombus formation and cardiovascular events.

Plasma therapy in foals and adult horses

Although a range of plasma-based products (e.g., cryoprecipitate, albumin, platelet-rich plasma, individual coagulation factors) are available to human physicians, equine veterinarians are largely restricted to using whole blood, frozen plasma, and fresh frozen plasma for transfusions. The indications for frozen or fresh frozen plasma in human medicine are relatively limited, and there is little evidence supporting the efficacy of these products in many cases. Furthermore, many human physicians have concerns regarding disease transmission and anaphylactic reactions after administration of any plasma product. In equine medicine, plasma products have been used (1) to treat failure of passive transfer (FPT); sepsis; and coagulopathies; (2) as "antiendotoxin" agents; and (3) to provide colloidal support. The use of plasma should be carefully considered before administration because of potential (although rare) adverse reactions as well as expense. In addition, the benefits are uncertain in some equine patients.

Effect of Escherichia coli endotoxin on Archachatina marginata hemolymph coagulation system

CONTEXT

Archachatina marginata Swainson (Achatinidae) is found in Nigeria, West Africa. Its hemolymph is applied as a disinfectant to blades and fresh cuts of circumcision in Yorubaland. The hemolymph is also used in traditional medicine practice. Investigation into its anti-endotoxin response is being studied for the first time.

OBJECTIVE

This study determined whether endotoxin causes measurable and concentration-dependent protein coagulation in the separate hemolymph fractions and in hemocyte lysate (HL)/plasma mixtures.

MATERIALS AND METHODS

Endotoxin was prepared by inoculating 5% w/v dextrose with locally isolated Escherichia coli cells and incubated for 48 h before sterilization. Pyrogenicity was determined by rabbit test method and use the of LAL kit. Hemolymph fractions were exposed to endotoxin while controls were exposed to endotoxin-free water (0.025 EU/ml). HL/plasma (1:1 v/v) was exposed to varied endotoxin concentrations.

RESULTS

Data indicated significantly higher protein coagulates induced by endotoxin in all the hemolymph fractions (P < 0.05). Maximum protein coagulation in mixture of HL/plasma 1:1 was recorded. Exposure of HL/plasma at optimal ratio to varied endotoxin caused linear protein coagulation up to 1.0 EU/ml, beyond which it dropped significantly and unresponsive to further increase in endotoxin doses.

DISCUSSION AND CONCLUSION

There was endotoxin-induced protein coagulation, which is endotoxin concentration-dependent. The optimal coagulation observed for 1:1 HL/plasma mixture suggests stronger interaction between the hemocytes and the plasma in response to endotoxin. There are LPS-binding proteins in the plasma and hemocytes of A. marginata. This finding may be employed in detection and quantification of endotoxin in future.

Factor XI and XII as antithrombotic targets

PURPOSE OF REVIEW

Arterial and venous thrombosis are major causes of morbidity and mortality, and the incidence of thromboembolic diseases increases as a population ages. Thrombi are formed by activated platelets and fibrin. The latter is a product of the plasma coagulation system. Currently available anticoagulants such as heparins, vitamin K antagonists and inhibitors of thrombin or factor Xa target enzymes of the coagulation cascade that are critical for fibrin formation. However, fibrin is also necessary for terminating blood loss at sites of vascular injury. As a result, anticoagulants currently in clinical use increase the risk of bleeding, partially offsetting the benefits of reduced thrombosis. This review focuses on new targets for anticoagulation that are associated with minimal or no therapy-associated increased bleeding.

RECENT FINDINGS

Data from experimental models using mice and clinical studies of patients with hereditary deficiencies of coagulation factors XI or XII have shown that both of these clotting factors are important for thrombosis, while having minor or no apparent roles in processes that terminate blood loss (hemostasis).

SUMMARY

Hereditary deficiency of factor XII (Hageman factor) or factor XI, plasma proteases that initiate the intrinsic pathway of coagulation, impairs thrombus formation and provides protection from vascular occlusive events, while having a minimal impact on hemostasis. As the factor XII-factor XI pathway contributes to thrombus formation to a greater extent than to normal hemostasis, pharmacological inhibition of these coagulation factors may offer the exciting possibility of anticoagulation therapies with minimal or no bleeding risk.

Improvement of spatial fibrin formation by the anti-TFPI aptamer BAX499: changing clot size by targeting extrinsic pathway initiation

BACKGROUND

Tissue factor pathway inhibitor (TFPI) is a major regulator of clotting initiation and a promising target for pro- and anticoagulation therapy. The aptamer BAX499 (formerly ARC19499) is a high-affinity specific TFPI antagonist designed to improve hemostasis. However, it is not clear how stimulation of coagulation onset by inactivating TFPI will affect spatial and temporal clot propagation.

OBJECTIVE

To examine the BAX499 effect on clotting in a spatial, reaction-diffusion experimental system in comparison with that of recombinant activated factor VII (rVIIa).

METHODS

Clotting in plasma activated by immobilized tissue factor (TF) was monitored by videomicroscopy.

RESULTS

BAX499 dose-dependently improved coagulation in normal and hemophilia A plasma activated with TF at 2 pmole m(-2) by shortening lag time and increasing clot size by up to ~2-fold. The effect was TFPI specific as confirmed by experiments in TFPI-depleted plasma with or without TFPI supplementation. Clotting improvement was half-maximal at 0.7 nm of BAX499 and reached a plateau at 10 nm, remaining there at concentrations up to 1000 nm. The BAX499 effect decreased with TF surface density increase. RVIIa improved clotting in hemophilia A plasma activated with TF at 2 or 20 pmole m(-2) , both by shortening lag time and increasing spatial velocity of clot propagation; its effects were strongly concentration dependent.

CONCLUSIONS

BAX499 significantly improves spatial coagulation by inhibiting TFPI in a spatially localized manner that is different to that observed with rVIIa.

Evidence based evaluation of immuno-coagulatory interventions in critical care

Cochrane systematic reviews with meta-analyses of randomised trials provide guidance for clinical practice and health-care decision-making. In case of disagreements between research evidence and clinical practice, high quality systematic reviews can facilitate implementation or deimplementation of medical interventions into clinical practice. This applies especially to treatment of critically ill patients where interventions are most often costly and the clinical conditions are associated with high mortality.

OBJECTIVES

To assess the potential benefits or harms of 1) antithrombin III (AT III) for critically ill patients; 2) inhaled nitric oxide (INO) for acute respiratory distress syndrome (ARDS) and acute lung injury (ALI); 3) aerosolized prostacyclin for ARDS and ALI; 4) thrombelastography (TEG) or thromboelastometry (ROTEM) to monitor haemotherapy versus usual care in patients with massive transfusion.

METHODS

We performed four systematic reviews of relevant randomised clinical trials. To quantify the estimated effect of various interventions, we conducted meta-analyses, where appropriate, to determine intervention effects using the Cochrane Collaboration methodology, trial sequential analyses (TSA), the GRADE, and the PRISMA-guidelines when conducting our systematic reviews. All reviews were performed according to published protocols following the recommendations of the Cochrane Handbook for systematic reviews of interventions. We performed multiple subgroup and sensitivity analyses with regard to methodological quality and various clinical outcomes. Trials were identified through Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE Science Citation Index-Expanded, The Chinese Biomedical Database and LILACS. We included all randomized clinical trials. We hand-searched reference lists, reviews, and contacted authors and experts for additional trials. We searched ClinicalTrials.gov, Centre Watch Clinical Trials Listing Service and ControlledTrials.com for missed, unreported, or ongoing trials. We screened bibliographies of relevant articles and conference proceedings and wrote to trialists and pharmaceutical companies producing the drugs in question.

RESULTS

Four systematic reviews included a total of 44 trials with 5,551 patients. Only 15 of the trials were classified as trials with low risk of bias (high methodological quality) regarding generation of the allocation sequence, allocation concealment, blinding, follow-up and other types of bias. 1) Compared with placebo or no intervention, AT III did not significantly affect overall mortality (relative risk (RR) 0.96, 95% confidence interval (CI) 0.89 to 1.03). No subgroup analyses on risk of bias, populations of patients, or with and without adjuvant heparin yielded significant results. AT III significantly increased the risk of bleeding events (RR 1.52, 95% CI 1.30 to 1.78). 2) INO showed no statistically significant effect on overall mortality (RR 1.06, 95% CI 0.93 to 1.22) and in several subgroup and sensitivity analyses, indicating robust results. Limited data demonstrated no effect of INO on duration of ventilation, ventilator-free days, and length of stay in the intensive care unit and hospital. We found a statistically significant, but transient improvement in oxygenation in the first 24 hours, expressed as the ratio of PO2 to fraction of inspired oxygen (mean difference (MD) 15.91, 95% CI 8.25 to 23.56). However, INO appears to significantly increase the risk of renal impairment among adults (RR 1.59, 95% CI 1.17 to 2.16) but did not significantly affect the risk of bleeding or methaemoglobin or nitrogen dioxide formation. 3) We found only one small low risk of bias paediatric trial examining the role of aerosolized prostacyclin in ALI or ARDS. Based on this limited amount of data, we were unable to support or refute the routine use of this intervention in ALI or ARDS. 4) Compared with standard treatment, TEG or ROTEM showed no statistically significant effect on overall mortality (RR 0.77, 95% CI 0.35 to 1.72) but only five trials provided data on mortality. Our analyses demonstrated a statistically significant effect of TEG or ROTEM on the amount of bleeding (MD -85.05 ml, 95% CI -140.68 to -29.42) but failed to show any statistically significant effect on other predefined outcomes. However, whether this reduction has implication for the patient's clinical condition is still uncertain.

CONCLUSION

We did not find reliable evidence to support the clinical use of the assessed immuno-coagulatory interventions for general use in critical care based on the available evidence. A large proportion of the trials had serious methodological shortcomings, small number of patients, and short trial duration. The sparse data provided in the included trials may be or may not be promising but is not necessarily evidence of absence of a beneficial or harmful effect, because many of the outcome measures have not been adequately addressed so far. There is an urgent need for several randomised clinical trials with low risk of bias and low risk of random error to evaluate the use of the assessed interventions.

Evaluation of hemostatic factors in patients undergoing major hepatic resection and other major abdominal surgeries

The aim of this study was to evaluate the role for additional testing of coagulation in perioperative management of patients undergoing major hepatic resection. Major outcome measures were perioperative measurements of hemostatic factors (activated partial prothrombin time [aPTT], prothrombin time/international normalized ratio, fibrinogen, antithrombin-III). We conducted a prospective, single-blind study comparing hemostatic factors in patients undergoing major hepatectomy, Whipple procedures, and other gastrointestinal operations. Ninety-five consecutive patients were enrolled. No values differed significantly at baseline. Immediately postoperative, only international normalized ratio was significantly lower comparing major hepatectomy with Whipple (P < 0.005) and other procedures (P < 0.0032). Twenty-four hours postoperative, antithrombin-III was lower for major hepatectomy than Whipple (P < 0.028) and others (P < 0.0001); fibrinogen was lower compared with Whipple (P < 0.014) and others (P < 0.0009); international normalized ratio was lower to compared with Whipple (P < 0.0001) and others (P < 0.0001). aPTT measurements never differed significantly between groups at any time. Antithrombin-III and fibrinogen only correlated with international normalized ratio and aPTT for the other procedures. Additional hemostatic values beyond the standard evaluations of aPTT and international normalized ratio are needed to better assess patients undergoing major hepatic surgery.

Research on the correlation between platelet gelsolin and blood-stasis syndrome of coronary heart disease

OBJECTIVE

To study the distribution of gelsolin in human platelet and plasma, and the association with blood-stasis syndrome (BSS) of coronary heart disease (CHD).

METHODS

Sixty patients with CHD (30 in BSS group and 30 in non-BSS group) and 30 healthy subjects (control group) were included in this study. The classification of the syndrome was based on clinical symptoms and signs. Gelsolin concentration in platelet rich plasma (PRP), platelet poor plasma (PPP), filamentous actin (F-actin) and group-specific component globulin (Gc-globulin) of PPP were determined by enzyme-linked immunosorbent assay (ELISA). The fluorescence intensity of CD62p and cytoplasmic calcium ([Ca(2+)](i)) in human platelets of patients and healthy persons was measured with flow cytometry.

RESULTS

Compared with the control group, gelsolin in PRP of the BSS group increased significantly (P<0.01), while that in PPP of the BSS and non-BSS groups decreased markedly (P<0.05), the CD62p, [Ca(2+)](i) of platelet, F-actin, and Gc-globulin of the BSS and non-BSS groups increased significantly (P<0.01). Compared with the non-BSS group, the gelsolin concentration in PRP of BSS group increased significantly (P<0.01), the [Ca(2+)](i) of platelet of the BSS group increased markedly (P<0.01), while the F-actin and Gc-globulin of the BSS group had no statistical defference (P>0.05).

CONCLUSIONS

Gelsolin concentration in PRP was increased and accompanied by the elevated [Ca(2+)](i) of platelet in CHD with BSS, while gelsolin in PPP were lowered markedly. We speculate that plasma gelsolin may clear F-actin from circulation, thus resulting in depletion of plasma gelsolin significantly. This, in addition to the increased calcium influx of platelets, may lead to the gelsolin abnormal expression on platelets during the process of BSS in CHD. Therefore, platelet gelsolin may serve as a new potential biomarker and a therapeutic target of BSS in CHD.

IL-1β down-regulates ADAMTS-13 mRNA expression in cells of the central nervous system

ADAMTS-13 is the Von Willebrand factor (vWF) cleaving protease, responsible for the cleavage and down-regulation of the pro-thrombotic properties of ultra large VWF multimers. It is expressed predominantly by the hepatic stellate cells of the liver, but is also found to be expressed in other tissues, including brain. Reduced ADAMTS-13 is associated with a variety of thrombotic microangiopathies. Since the cellular origin and regulation of ADAMTS-13 expression in the brain is unknown, we aimed to investigate this in four different central nervous system (CNS)-derived cell lines, SHSY-5Y (human neuroblastoma), U373 (human astroglioma), CHME-3 (human foetal microglia) and hCMEC/D3 (adult human brain endothelial cells). All cell lines expressed ADAMTS-13 mRNA constitutively with neuroblastoma cells showing the highest expression. Interleukin (IL)-1β down-regulated ADAMTS-13 mRNA expression in astroglioma cells and microglial cells whereas TNF and IL-6 treatment showed no significant differences in ADAMTS-13 mRNA expression in any cell line tested. ADAMTS-13 protein expression was reduced in a dose-dependent manner only in astroglioma cells following stimulation by IL-1β. The ability of IL-1β to significantly reduce ADAMTS-13 mRNA expression in human microglia and astroglioma cells suggests a role in the haemostasis of the local microenvironment under inflammatory conditions. This is the first report of ADAMTS-13 expression in cells of the CNS; however, its function remains to be determined.

Molecular cloning, in vitro expression and functional characterization of canine ADAMTS13

A disintegrin and metalloproteinase with thrombospondin type 1 motifs, number 13 (ADAMTS13) is a plasma zinc metalloprotease also known as von Willebrand factor (VWF)-cleaving protease. Deficiency of ADAMTS13 activity is known to cause thrombotic thrombocytopenic purpura (TTP) in humans. We isolated the canine ADAMTS13 cDNA, which encodes 1502 amino acids, and expressed the recombinant protein to evaluate VWF-cleaving ability. Although the propeptide domain was longer and the TSP1 repeat domain was shorter than those in other species, the overall structures were similar to human and mouse ADAMTS13. Recombinant canine ADAMTS13 cleaved the 250-kDa VWF monomer into two fragments of 150 kDa and 120 kDa. Furthermore, high molecular weight VWF multimers were abolished based on the activity of ADAMTS13. These results could facilitate research into hemostatic disorders such as TTP in dogs.

Hemostatic agents

Hemostasis is an integral and very important aspect of surgical practice. As a rule, most bleeding from dental surgery can be controlled by pressure. When the application of pressure does not yield satisfactory results, or where more effective hemostasis is required, hemostatic agents are used. These agents act to stop bleeding either mechanically or by augmenting the coagulation cascade. Some of the newer agents that are available to the dental profession have been presented.

Hemostatic response in paediatric patients undergoing cardiopulmonary bypass surgery

This prospective, single-center cohort study aimed to evaluate the hemostatic response during and after Cardiopulmonary Bypass (CPB) surgery in a large cohort of children up to 6 years of age. Blood samples were drawn at eight time points: post-induction of anesthesia, pre-unfractionated heparin (UFH), post-UFH, post-initiation of bypass, pre-protamine, post-protamine, post-chest-closure, and 6 h post-chest-closure. As expected, all measures of the UFH effect increased significantly post-UFH bolus and decreased post-protamine administration. However, thrombin generation remained inhibited compared to baseline values despite the post-UFH reversal by protamine. We also demonstrate that residual UFH effect is not responsible for the ongoing inhibition of thrombin observed post-protamine administration. The significant increase in both free and total tissue factor pathway inhibitor levels during the CPB surgery might contribute to the persistent thrombin generation/endogenous thrombin potential inhibition post-protamine administration. This study makes a significant and novel contribution by investigating the physiological mechanisms behind the degree of thrombin inhibition by UFH and the residual levels of thrombin inhibition that continue despite protamine reversal and provides a new foundation for future interventional studies in the setting of paediatric CPB surgery.

Haemostatic and cytokine changes in gestational diabetes mellitus

BACKGROUND

Limited data indicate the existence of a hypercoagulable state and the possible involvement of pro-inflammatory cytokines in the pathogenesis of gestational diabetes mellitus (GDM).

AIM

To characterise the coagulation inhibitor and cytokine profiles in women with GDM.

METHODS

Two groups of women in the third trimester of pregnancy were studied: GDM (n = 150) and controls: women with normal pregnancy (n = 100); GDM in their first post-delivery day (n = 52). LABORATORY ASSAYS: Plasma fibrinogen, antithrombin (AT), protein C, total and free protein S, interleukins-2, 6 and 8 (IL-2, 6, 8).

RESULTS

During pregnancy, the only significant alterations noted were higher levels of body mass index, fibrinogen and total protein S in women with GDM when compared to normal pregnancy. In the post-delivery group, there was further elevation in the levels of plasma fibrinogen and significant drop in the level of total protein S, protein C and AT. Significant elevation of IL-2 and IL-6 levels was recorded only in post-delivery group.

CONCLUSION

In GDM, the only indicator of a tendency towards hypercoagulability is the higher fibrinogen levels as compared to normal pregnancy. This feature along with the higher body mass index and presumed associated insulin resistance suggests that GDM may be a mild form of the metabolic syndrome. The lack of significant change in the levels of pro-inflammatory cytokines do not support the existence of an inflammatory state in GDM.

[Association between hemostasis/coagulation-system parameters and clinicopathological factors in patients with primary lung cancer]

Previous studies have gradually clarified the relationship between cancer and blood coagulation disorder and its mechanism. Various studies have also reported the association between lung cancer and coagulation disorder. However, it is rare to measure most hemostasis/coagulation-system test parameters in clinical practice. In this study, we investigated the association of hemostasis/coagulation-system test parameters, such as the prothrombin time (PT), activated partial thromboplastin time (APTT), bleeding time, and platelet count, which are routinely measured as preoperative examination parameters in patients with lung cancer, with the histopathologically evaluated stage of lung cancer. Although the mean values of hemostasis/coagulation-system parameters in all subjects were within the normal ranges, there were significant changes with respect to the clinico-pathological factors, showing a specific tendency. In patients in whom the histopathological stage was advanced, the APTT was prolonged, or the platelet count was increased.

[Practical recommendations for the use of coagulometers]

The paper describes the basic stages of operation on APH2-02, APH2-02-P, and APH4-02-P coagulometers. The operating sequence is considered when carrying out the prothrombin test, the most common coagulology test in the laboratories of Russia. In addition, recommendations are given, which allow the most typical errors to be avoided.

[Clinical application of the plasma substitutes in patients with postoperative complications after surgeries for brain meningioma]

The issues on optimization of the restoration treatment of patients, suffering the brain meningioma, were discussed, basing on analysis of 498 observations. Tactics of the patients management in noncomplicated, complicated and severe course of postoperative period is adduced. The indices of survival and lethality, peculiarities of the infusion therapy were analyzed. The role of plasm-restituting preparations was demonstrated in complicated course of postoperative period. Rational complex approach to the restoration measures and intensive therapy conduction promotes the treatment efficacy raising, the patients fair quality of life securing in the brain meningioma in postoperative period.

Blood coagulation dynamics: mathematical modeling and stability results

The hemostatic system is a highly complex multicomponent biosystem that under normal physiologic conditions maintains the fluidity of blood. Coagulation is initiated in response to endothelial surface vascular injury or certain biochemical stimuli, by the exposure of plasma to Tissue Factor (TF), that activates platelets and the coagulation cascade, inducing clot formation, growth and lysis. In recent years considerable advances have contributed to understand this highly complex process and some mathematical and numerical models have been developed. However, mathematical models that are both rigorous and comprehensive in terms of meaningful experimental data, are not available yet. In this paper a mathematical model of coagulation and fibrinolysis in flowing blood that integrates biochemical, physiologic and rheological factors, is revisited. Three-dimensional numerical simulations are performed in an idealized stenosed blood vessel where clot formation and growth are initialized through appropriate boundary conditions on a prescribed region of the vessel wall. Stability results are obtained for a simplified version of the clot model in quiescent plasma, involving some of the most relevant enzymatic reactions that follow Michaelis-Menten kinetics, and having a continuum of equilibria.

Plasminogen activator inhibitor-1 inhibits factor VIIa bound to tissue factor

BACKGROUND AND OBJECTIVE

A growing body of experimental evidence supports broad inhibitory and regulatory activity of plasminogen activator inhibitor 1 (PAI-1). The present study was designed to investigate whether PAI-1 inhibits factor (F) VIIa complexed with tissue factor (TF), a well-known procoagulant risk factor.

METHODS AND RESULTS

The ability of PAI-1 to inhibit FVIIa-TF activity was evaluated in both clotting and factor X (FX) activation assays. PAI-1 and its complex with vitronectin inhibit: (i) clotting activity of FVIIa-TF (PAI-1(IC50) , 817 and 125 nm, respectively); (ii) FVIIa-TF-mediated FX activation (PAI-1(IC50) , 260 and 50 nm, respectively); and (iii) FVIIa bound to TF expressed on the surface of stimulated endothelial cells (PAI-1(IC50) , 260 and 120 nm, respectively). The association rate constant (k(a)) for PAI-1 inhibition of FVIIa-TF was determined using a chromogenic assay. K(a) for PAI-1 inhibition of FVIIa bound to relipidated TF is 3.3-fold higher than that for FVIIa bound to soluble TF (k(a) = 0.09 ± 0.01 and 0.027 ± 0.03 μm(-1) min(-1), respectively). Vitronectin increases k(a) for both soluble and relipidated TF by 3.5- and 30-fold, respectively (to 0.094 ± 0.020 and 2.7 ± 0.2 μm(-1) min(-1)). However, only a 3.5- to 5.0-fold increase in the acylated FVIIa was observed on SDS PAGE in the presence of vitronectin for both relipidated and soluble TF, indicating fast formation of PAI-1/vitronectin/FVIIa/relipidated TF non-covalent complex.

CONCLUSIONS

Our results demonstrate potential anticoagulant activity of PAI-1 in the presence of vitronectin, which could contribute to regulation of hemostasis under pathological conditions such as severe sepsis, acute lung injury and pleural injury, where PAI-1 and TF are overexpressed.

The link between inflammation and coagulation: influence on the interpretation of diagnostic laboratory tests

This article provides an overview of the complex relationship between inflammation and coagulation and a review of routinely available laboratory and point-of-care tests for the detection of inflammation and coagulopathies. In the management of cases requiring ongoing laboratory and clinical evaluation, examination of these two major pathologic processes may assist with diagnosis and improve outcome. Early identification of a pathologic inflammatory process may allow prevention of its progression to syndromes carrying a poorer prognosis, such as disseminated intravascular coagulation and multiple organ dysfunction syndrome.

Method for in vitro analysis of nanoparticle thrombogenic properties

Thrombus formation is complex process involving both cellular and molecular (protein) components. Platelets are responsible for maintaining hemostasis and for preventing excessive bleeding. These cells aggregate along with other plasma components and blood cells to form blood clots. Undesirable platelet aggregation may lead to life-threatening conditions such as stroke. Thrombogenicity is the property of a material to induce the formation of a thrombus, which results in partial or complete occlusion of a blood vessel. The tendency to cause platelet aggregation and perturb plasma coagulation can serve as an in vitro measure of a nanomaterial's likelihood to be thrombogenic in vivo. This chapter describes a procedure for in vitro analyses of platelet aggregation and plasma coagulation time. Platelet-rich plasma (PRP) is obtained from freshly derived human whole blood and incubated with nanoparticles. Then the plasma is examined using a particle count and size analyzer to determine the number of active platelets. The percent aggregation is calculated by comparing the number of active platelets in the nanoparticle-exposed sample to control plasma. To measure the plasma coagulation time, platelet-poor plasma from human whole blood is exposed to nanoparticles in vitro and analyzed in prothrombin (PT), activated partial thromboplastin (APTT), and thrombin time assays.

[Dynamics of primary hemostasis activity in patients with arterial hypertension and metabolic syndrome treated with candesartan]

The aim of the study was to elucidate normalizing effect of candesartan on disturbed thrombocytic hemostasis in patients with arterial hypertension and metabolic syndrome. The drug was given for 16 weeks to 31 patients in whom dynamics of lipid peroxidation in plasma and platelets, the antioxidative potential of candesartan, and parameters of thrombocytic hemostasis were assessed. Treatment with candesartan improved lipid peroxidation and primary hemostasis. It is expected that continuation of therapy following this scheme can stabilize the obtained effect.

[Pathogenetic aspects of arterial hypertension in metabolic syndrome]

Arterial hypertension (AH) remains a topical problem in modern cardiology. It increases the risk of angina, myocardial infarction, stroke, neurologic and psychic disorders. Causes, symptoms, criteria and method for the correction of AH in patients with metabolic syndrome are extensively investigated. However, disturbances of hemostasis and approaches to their efficacious correction in such patients remains unexplored.

[State of the endothelium and hemostasis in acute leukemia]

The review presents modern conceptions of disturbances in endothelial lining of the vessels and plasmic hemostasis in patients with acute leukemia; different mechanisms of coagulation disorders in acute leukemia: effects of leukemic cells containing procoagulants, fibrinolytic and antifibrinolytic substances, of intensive chemotherapy and inflammation. All these impacts impair endothelial cells and trigger plasmic coagulation cascade; the initiator of coagulation is a tissue factor. Mechanisms of this process and statistics of thrombohemorrhagic complications in different variants of acute leukemia are outlined.

[Water-electrolyte homeostasis and hemostasis system after transurethral resection of the prostate]

Changes in coagulogram and water-electrolyte homeostasis were studied in 89 patients surgically treated for prostatic adenoma (TUR). The patients were divided into 2 groups: group 1 (n=21) was operated with use of distilled water, group 2--with 5% glucose solution. The following examinations were made in all the patients: extended coagulogram, total blood count, concentration of electrolytes, creatinin, plasma urea and glucose, osmolality measurements. These were made thrice: before the operation, on postoperative day 1, postoperative day 3. Postoperative changes of hemostasis and water-electrolyte homeostasis of plasma were less significant in group 2. The risk of postoperative hemorrhage is higher in patients of group 1.

Activity of platelet hemostasis in children with spinal deformities

An increase of adhesion and aggregation functions of platelets in vivo and in vitro was detected in 5-6-year-old children with scoliosis. These disorders were caused by hyperproduction of von Willebrand's factor in the vascular wall and intensification of thromboxane production in blood platelets. Activation of thromboxane formation is the main cause of platelet hyperactivity in children with scoliosis. Correction of platelet hemostasis may include pathogenetically substantiated complex of therapeutic exercises, swimming, and massage.

Cystathionine beta-synthase null homocystinuric mice fail to exhibit altered hemostasis or lowering of plasma homocysteine in response to betaine treatment

Cystathionine beta-synthase (CBS) deficient homocystinuria is an inherited metabolic defect that if untreated typically results in mental retardation, thromboembolism and a range of connective tissue disturbances. A knockout mouse model has previously been used to investigate pathogenic mechanisms in classical homocystinuria (Watanabe et al., PNAS 92 (1995) 1585-1589). This mouse model exhibits a semi-lethal phenotype and the majority of mice do not survive the early neonatal period. We report here that the birth incidence of cbs (-/-) mice produced from heterozygous crosses is non-Mendelian and not significantly improved by treatment with either the Hcy lowering compound betaine or the cysteine donor N-acetylcysteine. Betaine treatment did improve survival of cbs (-/-) mice and restored fertility to female cbs (-/-) mice but did so without significantly lowering Hcy levels. Surviving cbs (-/-) mice failed to show any alteration in coagulation parameters compared to wild-type controls. Moribund cbs (-/-) mice exhibited severe liver injury and hepatic fibrosis while surviving cbs (-/-) mice although less severely affected, still exhibited a level of severe liver injury that is not found in the human disease. The hepatopathy observed in this model may offer an explanation for the failure of cbs (-/-) mice to respond to betaine or exhibit a hypercoagulative phenotype. We conclude that although this model provides useful data on the biochemical sequelae of classical homocystinuria, it does not successfully recapitulate a number of important features of the human disease and its use for studying mechanisms in homocystinuria should be treated with caution as the hepatopathy produces changes which could influence the results.

Evolving materials and techniques for endoscopic sinus surgery

Functional endoscopic sinus surgery was initially introduced as a minimally invasive procedure to treat chronic rhinosinusitis (CRS) in patients for whom medical management failed. Sinus surgery has been deemed an extremely effective part of the overall management of chronic sinus disease with symptomatic improvement in the vast majority of patients. At the forefront, technologic advances have been critical in advancing endoscopic sinus surgical procedures. With the introduction of improved optics and lighting, advanced instrumentation, and image-guided surgical navigation, the limitations of endoscopic procedures have been significantly reduced. Endoscopic techniques have evolved to include the management of both malignant and benign neoplasms of the sinuses and anterior skull base. This article highlights some of the newest advances in technology, materials, and medical/surgical techniques used in endoscopic sinus and skull base procedures and illustrates how they advance overall patient care to help minimize morbidity and complications.