The Release of Plasminogen Activator and Factor VIII after Injection of DDAVP in Healthy Volunteers and in Patients with von Willebrand's Disease

Effect of perioperative desmopressin in cats with mammary carcinoma treated with bilateral mastectomy

Perioperative administration of desmopressin has shown to significantly decrease rates of local recurrence and metastasis, and increase survival times in dogs with grade II and III mammary carcinomas. The objective of this study was to compare the oncologic outcome of cats with mammary carcinoma treated with bilateral mastectomy with or without perioperative administration of desmopressin. Medical records from nine veterinary institutions were searched to identify cats diagnosed with mammary carcinoma treated with bilateral mastectomy. Sixty cats treated with single-session or staged bilateral mastectomy were included. There were no significant differences in oncologic outcomes found between cats treated and not treated with desmopressin. No adverse effects were seen in any of the cats treated with perioperative desmopressin. Postoperative complications occurred in 18 cats (38.3%) treated with single-session bilateral mastectomy and in three cats (23.1%) treated with staged bilateral mastectomy (P = .48). Histologic grade and a modification of a proposed five-stage histologic staging system were both prognostic for disease-free interval. Incomplete histologic excision was associated with significantly increased rates of metastasis and tumour progression, and a shorter median survival time (MST). Cats that developed local recurrence also had a significantly shorter MST. The results of this study do not support the use of perioperative desmopressin to improve outcome when performing bilateral mastectomy for the treatment of mammary carcinoma in cats.

Targeting of a Heterologous Protein to a Regulated Secretion Pathway in Cultured Endothelial Cells

The stimulation of regulated exocytosis in vascular endothelial cells (EC) by a variety of naturally occurring agonists contributes to the interrelated processes of inflammation, thrombosis, and fibrinolysis. The Weibel-Palade body (WPB) is a well-described secretory granule in EC that contains both von Willebrand factor (vWF) and P-selectin, but the mechanisms responsible for the targeting of these proteins into this organelle remain poorly understood. Through adenoviral transduction, we have expressed human growth hormone (GH) as a model of regulated secretory protein sorting in EC. Immunofluorescence microscopy of EC infected with GH-containing recombinant adenovirus (GHrAd) demonstrated a granular distribution of GH that colocalized with vWF. In contrast, EC infected with an rAd expressing the IgG1 heavy chain (IG), a constitutively secreted protein, did not demonstrate colocalization of IG and vWF. In response to phorbol ester, GH as well as endogenously synthesized vWF were rapidly released from GHrAd-infected EC. By immunofluorescence microscopy, granular colocalization of GH with endogenous tissue-type plasminogen activator (tPA) was also demonstrated, and most of the tPA colocalized with vWF. These data indicate that EC are capable of selectively targeting heterologous proteins, such as GH, to the regulated secretory pathway, which suggests that EC and neuroendocrine cells share common protein targeting recognition signals or receptors.

Desmopressin in the treatment of women's bleeding disorders

Bleeding disorders in women are an underestimated problem that deserves increased attention. About 9%-14% of females have menorrhagia and, amongst them, there is a significant over-representation of von Willebrand disease (VWD), with a prevalence of 13% in this group as compared with about 1% in the general population. The bleeding disorder has not been diagnosed in most of these women and they may therefore be withheld from treatment with desmopressin, which is effective in most cases of VWD and also in platelet dysfunctions and mild factor VIII deficiency. This paper is a review of the haemostatic use of desmopressin with special reference to women's bleeding disorders, the mechanisms of action, modes of administration, clinical indications, dosage recommendations, and hospital or home treatment. Desmopressin stimulates endogenous release of FVIII and von Willebrand factor (VWF), it increases platelet adhesiveness and shortens bleeding time. It can be given as intravenous or subcutaneous injection, but the intranasal spray is probably the most practical mode of administration for females with bleeding disorders as it is simple to administer and suitable for home treatment. The spray has been used successfully in connection with menorrhagia and other bleeding symptoms.

Evidence of a Local Mechanism for Desmopressin-Induced Tissue-Type Plasminogen Activator Release in Human Forearm

Systemic administration of desmopressin (DDAVP) induces increased plasma levels of tissue-type plasminogen activator (t-PA), coagulation factor VIII, and von Willebrand factor (vWF). However, the mechanisms behind these responses are not known. We tested the hypothesis that DDAVP acts as a local stimulator of acute endothelial release of t-PA and vWF independently of central pathways. Healthy, young, nonsmoking male volunteers were studied. In a first study (n = 7), DDAVP and placebo were administered as randomized single-blind stepwise intrabrachial artery infusions (0.7, 7.0, and 70 ng/min). In a another subset of subjects (n = 4), a constant-rate DDAVP infusion of 70 ng/min was administered for 20 minutes in the brachial artery of the nondominant arm with the dominant arm as control. To rule out that the observed t-PA release was flow-dependent, 4 additional subjects received stepwise intra-arterial infusions of both DDAVP (7.0, 21, and 70 ng/min) and sodium nitroprusside (SNP; 0.5, 2.5, and 10 μg/min). Brachial venoarterial plasma concentration gradients and forearm plasma flow were used to determine net release/uptake rates of t-PA and vWF. At baseline, the average net release rate of t-PA was 6.7 ng/min across the whole forearm vascular bed, whereas there was no detectable basal release of vWF. Stepwise infusion of DDAVP induced a massive regulated release of t-PA with a peak after 15 minutes on the highest dose-step (ANOVA; P < .0001). The average maximum net release rate was 178 ng/min, and the total amount of t-PA released was, on the average, 3,000 ng. The majority was released in its active form. Constant-rate DDAVP infusion again markedly increased t-PA release in the infusion arm but had no effect whatsoever in the control arm. In contrast, DDAVP did not stimulate a local release of vWF in either study. Central hemodynamics were unchanged during infusions despite a local vasodilatory response with DDAVP. Endothelium-independent flow stimulation by SNP did not elicit any local t-PA release. We conclude that DDAVP induces a massive acute flow-independent release of t-PA, without the simultaneous release of vWF, in the human forearm vascular bed. The lack of a t-PA response in the control arm, as well as the unaltered central hemodynamics with DDAVP, confirms that the observed regulated t-PA release is local and independent of central mechanisms.

Evidence of a Local Mechanism for Desmopressin-Induced Tissue-Type Plasminogen Activator Release in Human Forearm

Systemic administration of desmopressin (DDAVP) induces increased plasma levels of tissue-type plasminogen activator (t-PA), coagulation factor VIII, and von Willebrand factor (vWF). However, the mechanisms behind these responses are not known. We tested the hypothesis that DDAVP acts as a local stimulator of acute endothelial release of t-PA and vWF independently of central pathways. Healthy, young, nonsmoking male volunteers were studied. In a first study (n = 7), DDAVP and placebo were administered as randomized single-blind stepwise intrabrachial artery infusions (0.7, 7.0, and 70 ng/min). In a another subset of subjects (n = 4), a constant-rate DDAVP infusion of 70 ng/min was administered for 20 minutes in the brachial artery of the nondominant arm with the dominant arm as control. To rule out that the observed t-PA release was flow-dependent, 4 additional subjects received stepwise intra-arterial infusions of both DDAVP (7.0, 21, and 70 ng/min) and sodium nitroprusside (SNP; 0.5, 2.5, and 10 μg/min). Brachial venoarterial plasma concentration gradients and forearm plasma flow were used to determine net release/uptake rates of t-PA and vWF. At baseline, the average net release rate of t-PA was 6.7 ng/min across the whole forearm vascular bed, whereas there was no detectable basal release of vWF. Stepwise infusion of DDAVP induced a massive regulated release of t-PA with a peak after 15 minutes on the highest dose-step (ANOVA; P < .0001). The average maximum net release rate was 178 ng/min, and the total amount of t-PA released was, on the average, 3,000 ng. The majority was released in its active form. Constant-rate DDAVP infusion again markedly increased t-PA release in the infusion arm but had no effect whatsoever in the control arm. In contrast, DDAVP did not stimulate a local release of vWF in either study. Central hemodynamics were unchanged during infusions despite a local vasodilatory response with DDAVP. Endothelium-independent flow stimulation by SNP did not elicit any local t-PA release. We conclude that DDAVP induces a massive acute flow-independent release of t-PA, without the simultaneous release of vWF, in the human forearm vascular bed. The lack of a t-PA response in the control arm, as well as the unaltered central hemodynamics with DDAVP, confirms that the observed regulated t-PA release is local and independent of central mechanisms.

High capacity for tissue-type plasminogen activator release from vascular endothelium in vivo

BACKGROUND

Tissue-type plasminogen activator (t-PA) is the key mediator of intravascular fibrinolysis. We showed recently that local administrations both of methacholine (MCH) and of desmopressin (1-desamino-8-D-arginine vasopressin, DDAVP) induced a massive local release of t-PA in the human forearm vasculature.

OBJECTIVE

To determine whether the human vascular endothelium could respond to repeated stimulation with the same agonist, and, if so, to further evaluate the releasable endothelial pool of t-PA.

METHOD

Seven young, healthy men participated. MCH and DDAVP were administered as local infusions into the brachial artery. In protocol 1 (n = 3) 2 microg/min MCH was infused for 2 (30 min with a free interval of 20 min). In protocol 2 (n = 4) 70 ng/min DDAVP was infused for 2 (20 min with an interval of 75 min). Dosages and time intervals were based on the different release profiles of the two drugs observed in previous studies. Brachial arterial and venous blood samples were obtained at baseline and throughout infusions. Net release of t-PA was calculated as the product of the arteriovenous concentration gradient and forearm plasma flow.

RESULTS

Forearm blood flow was increased 3-4-fold by MCH and 2-3-fold by DDAVP infusions. During the first and second infusions of MCH, the average amounts of t-PA released were 1600 and 1000 ng/l forearm tissue, respectively. In contrast, DDAVP induced similar t-PA responses during both infusions; the average total releases of t-PA were 2300 and 2400 ng/l tissue, respectively.

CONCLUSION

The results show that the vascular endothelium is responsive to repeated stimulation both with MCH and with DDAVP. The diminished t-PA response to the second MCH infusion can not be explained in terms of depletion of intracellular pools, in view of the large amount of t-PA released by a single infusion of DDAVP. The dynamic pool of t-PA available for release is very large, but further studies are required in order to quantify the releasable endothelial stores.

The treatment of haemophilia, including prophylaxis, constant infusion and DDAVP

Recent years have witnessed advances in the treatment of haemophilia such as the introduction of prophylaxis, continuous infusion and pharmacological treatment with desmopressin (DDAVP). Prophylactic treatment on a long-term basis appears to be effective in preventing the development of arthropathy in severe haemophilia. The largest body of experience is that from Sweden, where prophylaxis is started at the age of 1-2 years. The dosage used is 25-40 U factor VIII/IX per kilogram bodyweight given three times or twice weekly, respectively. In some cases an intravenous access device has to be used during the first years of treatment. The patients grow up like normal boys and can live virtually normal lives. The beneficial psychological impact of prophylaxis on the family cannot be overestimated. Side-effects are not more frequent with prophylaxis than with on-demand treatment. The feasibility of continuous infusion of factor VIII/IX concentrates during bleeding episodes, or as cover for surgery, has been documented. This mode of delivery increases convenience and the cost-benefit ratio of the treatment, with savings in postoperative replacement of factor concentrate of about 50-75%. Many modern concentrates are stable enough for the purpose, and several pump systems, including portable ones, are available. The haemostatic drug DDAVP can be effectively used in most cases of mild haemophilia A. Intravenous administration is to be preferred as cover for surgery or in the case of severe bleeds. There is an effective nasal spray which can also be used for home therapy in mild or moderate bleedings.

Isolation and characterization of tissue-type plasminogen activator- binding proteoglycans from human umbilical vein endothelial cells

We analyzed the tissue-type plasminogen activator (TPA)-binding proteoglycans (PGs) on human umbilical vein endothelial cells (HUVECs), which were metabolically labeled with [35S]NA2SO4. Cell extracts were then prepared and subjected to affinity chromatography on diisopropyl fluorophosphate (DFP)-inactivated TPA-Sepharose 4B. Approximately 6% of the incorporated 35S radioactivity bound to DFP-treated TPA-Sepharose 4B and was eluted with 2 mol/L NaCl. In addition to NaCl, heparin, arginine, and lysine but not glycine, epsilon-amino-n-caproic acid or aspartic acid inhibited this binding and eluted the bound 35S radioactivity. Urea-containing polyacrylamide gel electrophoresis of the eluted material consistently revealed two main signals of 35S radioactivity (one with an M(r) between 600,000 and 750,000 [PGA] and the other with an M(r) between 120,000 and 180,000 [PGC]). Occasionally a less intense signal with an M(r) between 340,000 and 440,000 (PGB) was seen. Heparitinase treatment markedly decreased the intensities of both 35S signals (PGA and PGB), and chondroitinases AC and ABC abolished the 35S signal of PGC, indicating that most of the HUVEC-incorporated radioactivity with an affinity for TPA could be attributed to heparan sulfate- and chondroitin sulfate-like structures. Reductive elimination, which was performed to separate the possible glycosaminoglycan moieties from the core proteins, confirmed the PG-like nature of this material and again revealed heparan sulfate and chondroitin sulfate as the major glycosaminoglycan components. We therefore conclude that HUVECs synthesize TPA-binding, heparan sulfate- and chondroitin sulfate-containing PGs. In vivo, similar PGs may play a role in TPA binding to endothelial cells and thereby possibly influence TPA activity and/or provide an intravascular storage pool of TPA.

Renal biopsy in children: indications, technique and efficacy in 119 consecutive cases

Consecutive renal biopsies were performed on native kidneys in 109 children and adolescents, aged 0.1-19.8 (mean 9.9) years (119 biopsies). Bleeding diatheses were excluded or treated pre-operatively with intravenous desmopressin acetate. Biopsies were performed by a radiologist under ultrasound imaging, using an automated spring-loaded device allowing selection of the length of the needle movement and score size. Diagnostically adequate tissue was retrieved in 118 of 119 (99.2%) biopsy procedures; 24-h post-biopsy ultrasonography disclosed a small haematoma of the biopsied kidney in 26% of the cases. No correlation was seen between the occurrence of haematoma and (treated) prolonged bleeding time or a decrease in the haemoglobin level. No major complications occurred. Newly developed macroscopic haematuria was reported by 7% and micturition pain by 7% of patients. Painful body movements were reported by 37%. We conclude that the use of ultrasound imaging and an automated gunshot technique is a safe and efficient method for performing renal biopsies in paediatric patients.

Biological effect of desmopressin in eight patients with type 2N ('Normandy') von Willebrand disease. Collaborative Group

It is generally thought that the plasma increase in factor VIII (FVIII) after desmopressin (dDAVP) infusion is related to the plasma increase in von Willebrand factor (vWF), which is the plasma carrier for FVIII. The aim of this study was to evaluate the FVIII and vWF responses in patients with type 2N vWD, characterized by the mild FVIII deficiency related to markedly decreased affinity of vWF for FVIII. At different times after one intravenous dose of dDAVP (0.3 or 0.4 microgram/kg) we measured the FVIII coagulant activity, FVIII antigen, vWF antigen and ristocetin cofactor activity, in eight patients with either Arg91Gln or Arg53Trp amino acid substitution in mature vWF. In all the patients, whatever their mutation, the dDAVP infusion resulted in a 2.3 +/- 0.7-fold increase of vWF and a variable rise (9.5 +/- 7.7 times) of FVIII, whereas the vWF capacity to bind FVIII was not improved. The FVIII response was more transient than vWF response, and FVIII half disappearance time was evaluated to be approximately 3 h. The data indicate that the stabilizing effect of vWF on FVIII is not responsible for the FVIII increase induced by dDAVP. The clinical implication of this study is that, in the 2N vWD patients, dDAVP may be a useful prophylactic or curative treatment when the test dose has been shown to be effective to reach a haemostatic FVIII level.

Desmopressin (DDAVP) and hemostasis

Desmopressin is a widely used hemostatic drug. It is a synthetic analogue of the natural hormone vasopressin, but, in contrast to vasopressin, it has no pressor activity. The effect is immediate, with two- to sixfold increases in the plasma concentrations of coagulation factor VIII, on Willebrand factor, and tissue plasminogen activator, and increases in platelet adhesiveness of comparable magnitude. Desmopressin is used in patients with mild hemophilia A, von Willebrand's disease, congenital platelet dysfunction, or acquired platelet dysfunction due to uremia or intake of such drugs as aspirin. It may also be used to reduce surgical blood loss in patients without known bleeding diathesis. Optimal hemostatic effect is achieved with a dosage of 0.3 micrograms/kg given intravenously. Other routes of administration are subcutaneous injection or intranasal spray. The latter proved to be efficient for home treatment of patients with bleeding disorders.

Patients with severe von Willebrand disease are insensitive to the releasing effect of DDAVP: evidence that the DDAVP-induced increase in plasma factor VIII is not secondary to the increase in plasma von Willebrand factor

It is generally held that factor VIII (FVIII) does not increase in the plasma of severe von Willebrand disease (vWD) patients treated with DDAVP because they lack von Willebrand factor (vWF), which is the plasma carrier for FVIII. To test this hypothesis, FVIII plasma levels were monitored in severe vWD patients treated with DDAVP after normalization of vWF plasma levels with infusions of cryoprecipitate. Each of four severe vWD patients underwent four different treatments at intervals of at least 15 d: (1) cryoprecipitate plus DDAVP; (2) cryoprecipitate plus saline; (3) cryoprecipitate plus recombinant FVIII (rFVIII); (4) saline plus rFVIII. Cryoprecipitate increased the plasma levels of FVIII and vWF. The infusions of saline or DDAVP after cryoprecipitate did not further increase FVIII and vWF plasma levels and had no effect on the plasma levels of tissue plasminogen activator (tPA), which are raised by DDAVP in normal subjects and in patients with vWD of other types. The infusion of rFVIII further increased by 182 +/- 32 U/dl (mean +/- SEM) the plasma levels attained after cryoprecipitate, which disappeared from the circulation with a half-life of 11.95 +/- 0.86 h. In contrast, the infusion of rFVIII after saline increased by only 107 +/- 18 U/dl the plasma levels of FVIII, which disappeared from the circulation with a half-life of 2.68 +/- 0.14 h, indicating that the vWF infused with cryoprecipitate is able to bind additional FVIII. These studies indicate that DDAVP does not increase the plasma levels of FVIII in patients with severe vWD even after normalization of plasma vWF. The possibility is discussed that severe vWD patients may be insensitive to the releasing effect of DDAVP.

Antidiuretic activity and release of factor VIII by vasopressin analogues

Vasopressin and in particular its structural analogue dDAVP (1-deamino-8-D-arginine vasopressin) can increase plasma concentrations of Factor VIII and tissue plasminogen activator (tPA) in some species of animals and in humans. For this reason dDAVP is used therapeutically in the treatment of bleeding episodes in patients suffering from haemophilia A and Von Willebrand's disease. However, the high antidiuretic activity of dDAVP constitutes and unwanted effect in this context. In the present study, a large number of analogues of vasopressin were designed, synthesized and tested in monkeys with the aim of producing compounds in which the Factor VIII-releasing activity was selectively isolated from the vasopressor and antidiuretic actions of the peptide. The results indicate that it is possible to separate these biological activities; however, none of the analogues tested so far possessed Factor VIII potencies comparable to that of dDAVP.

Urokinase-type plasminogen activator release after DDAVP in von Willebrand disease: different behaviour of plasminogen activators according to the synthesis of von Willebrand factor

Nine healthy volunteers and 23 patients with various types of von Willebrand disease were studied before and after DDAVP infusion. We investigated the behaviour of factor VIII/von Willebrand factor measurements, and of tissue plasminogen activator and urokinase-type plasminogen activator. In mild von Willebrand disease the increase of both plasminogen activators was similar to that seen in normal controls. A different fibrinolytic behaviour was found in the type I platelet low and in the type III von Willebrand disease patients. An impaired and absent fibrinolytic response to DDAVP was seen in the former and in the latter von Willebrand disease, respectively. A close relation between either u-PA and t-PA or von Willebrand factor was observed. The possibility of a linkage among these three proteins was discussed.

Plasmin generation and fibrin(ogen)olysis following desmopressin infusion

Desmopressin acetate (DDAVP) is known to stimulate the release of tissue-type plasminogen activator (t-PA) from endothelial cells, but it is unclear whether the increased t-PA actually elicits the plasmin generation and fibrin(ogen)olysis in the circulating blood. We measured plasma levels of plasmin-alpha 2-plasmin inhibitor complex, fibrinogen degradation products (FgDP) and fibrin degradation products (FbDP) following desmopressin infusion in 19 patients with bleeding disorders or thrombophilia. Administration of desmopressin (0.3-0.4 microgram/kg) produced a 4.0-fold increase in plasmin-alpha 2-plasmin inhibitor complex at 30 min, whereas neither FgDP nor FbDP was elevated significantly. These findings indicate that desmopressin infusion provokes the generation of plasmin in vivo, but most of the plasmin generated is complexed to alpha 2-plasmin inhibitor and does not degradate fibrin or fibrinogen.

Bleeding time prolongation with streptokinase and its reduction with 1-desamino-8-D-arginine vasopressin

The mechanism by which treatment with thrombolytic agents causes bleeding is not known. Recently, frequency of bleeding events has been shown to correlate with bleeding time, particularly in individuals treated with aspirin. We examined the effects of streptokinase (20,000-60,000 IU/kg) on bleeding time in 40 rabbits pretreated with aspirin, a model for fibrinolytic therapy. We then tested the effects of 1-desamino-8-D-arginine vasopressin (DDAVP) (0.3 microgram/kg), an agent known to reduce bleeding time in a variety of bleeding disorders, in 20 rabbits and compared the results with those of a control group of rabbits receiving normal saline placebo. Aspirin increased the bleeding time from a baseline mean +/- SEM value of 119 +/- 15 to 191 +/- 34 seconds in the control group and from 114 +/- 6 to 188 +/- 18 seconds in the experimental group. The addition of streptokinase increased the bleeding time to 592 +/- 119 seconds in the control group and 810 +/- 114 seconds in the experimental group (p = NS). Subsequent infusion of DDAVP decreased the bleeding time in the experimental group to 302 +/- 29 seconds (p less than 0.01 versus streptokinase) compared with 572 +/- 79 seconds (p = NS versus streptokinase) in the control animals given saline placebo. In a subset of rabbits receiving aspirin and streptokinase (40,000-60,000 IU/kg), samples were obtained for platelet aggregation (n = 16), von Willebrand factor antigen concentration (n = 17), and von Willebrand factor multimer distribution (n = 14). Maximal rates of ADP-induced platelet aggregation were not affected by DDAVP infusion, nor was the plasma concentration of von Willebrand factor antigen, quantified by an immunoradiometric assay, significantly affected by DDAVP infusion. Furthermore, the von Willebrand factor multimer ratio decreased with DDAVP administration. These findings indicate that aspirin and streptokinase combined result in a marked increase in bleeding time that can be reduced by DDAVP. This effect of DDAVP is not accompanied by an increase in platelet aggregation response, plasma von Willebrand factor antigen concentration, or von Willebrand factor multimer ratio.

Use of DDAVP in inherited and acquired platelet dysfunction

Twenty-one patients with prolonged bleeding times secondary to inherited disorders of platelet function and eight patients with prolonged bleeding times secondary to acquired platelet dysfunction were given 0.3 micrograms per kilogram of DDAVP, 1-deamino-8-D-arginine vasopressin, intravenously. Sixteen of twenty-two DDAVP trials in patients with inherited platelet dysfunction (73%) and seven of the nine DDAVP trials in patients with acquired platelet dysfunction (78%) resulted in normalization or shortening of the prolonged bleeding times by at least 4 min. The bleeding time response did not correlate with changes in the levels of von Willebrand factor (vWf) antigen or ristocetin cofactor activity, nor was it associated with changes in vWf multimeric analysis or in vitro platelet aggregations following the administration of DDAVP. Shortening of the bleeding time with DDAVP was seen in patients with a failure to release/storage pool type defect, thromboxane synthesis type defect, Bernard-Soulier syndrome, Glanzmann's thrombasthenia, the May-Hegglin anomaly, liver disease, nonuremic renal disease, myelofibrosis, and Tangier's disease.

IIB von Willebrand's disease: pathogenetic and therapeutic studies

Infusion of 1-deamino-(8-D-arginine)-vasopressin (DDAVP) into patients with IIB von Willebrand's disease (vWD) has been reported to induce thrombocytopenia. In some families with this disorder thrombocytopenia is present even in the resting state. We have investigated the basis of this chronic thrombocytopenia in one such patient by performing platelet recovery and survival studies. Increased platelet consumption was suggested by a decrease in platelet recovery (40.5%, normal 45%) and mean platelet survival (112 h, normal range 144-224 h). In addition, we have administered test infusions of DDAVP and observed the effect on bleeding time and platelet count. DDAVP caused a decrease in the median platelet count from 86 x 10(9)/l (range 30-221) to 60 x 10(9)/l (range 5-144), the individual decline in the nine subjects ranging from 12% to 84% compared to the pretreatment values. Formation of platelet aggregates was observed in all patients following DDAVP. The bleeding time was prolonged before DDAVP in all patients and lengthened further in two after the infusion. However, partial correction of the bleeding time was seen in three and normalization in one patient following DDAVP infusion. Two IIB vWD patients were treated with virus-inactivated cryoprecipitate (Ristofact). Infusion of cryoprecipitate was followed by rapid appearance of all but the largest vWF multimers in plasma and did not affect the platelet count. The bleeding time was normalized in one patient but remained prolonged in the other. In conclusion, in IIB vWD patients virus-inactivated cryoprecipitate is the treatment of choice in the case of bleeding. Infusion of DDAVP might be effective in a subset of IIB vWD patients that has yet to be characterized.

Absence of functional activity of tissue plasminogen activator in patients with severe forms of von Willebrand's disease

Some patients with von Willebrand's disease do not respond to stimuli such as venous occlusion and infusion of a vasopressin analogue DDAVP. In these patients, fibrinolytic activity is not enhanced and von Willebrand's factor is not released into the blood. Skin biopsies and cryostat sections were used to study the fibrinolytic activity of skin vessels and localization of tissue plasminogen activator (t-PA) in three patients with severe form of von Willebrand's disease. On fibrin films, no fibrinolysis developed around the skin vessels of the patients; however, using specific polyclonal and monoclonal antibodies to t-PA, and peroxidase coupled specific IgG, presence of t-PA antigen was demonstrated in endothelial cells (EC) of all of them. In plasma no t-PA activity was detected either before or after venous occlusion although t-PA inhibitor activity was in a normal range. Small amounts of t-PA antigen was measured in blood by ELISA. From these results, it is concluded that in patients with severe forms of von Willebrand's disease, t-PA present in EC is not functional and can not transform plasminogen into plasmin.

Treatment of severe platelet dysfunction and hemorrhage after cardiopulmonary bypass: reduction in blood product usage with desmopressin

Impairment of platelet function commonly occurs after cardiopulmonary bypass, and may result in substantial bleeding. Because desmopressin acetate (a synthetic analogue of vasopressin) shortens bleeding time in a variety of platelet disorders, a controlled clinical trial of intravenous desmopressin was performed in 39 patients with excessive mediastinal bleeding (greater than 100 ml/h) and a prolonged template bleeding time (greater than 10 minutes) more than 2 hours after termination of cardiopulmonary bypass. Twenty-three desmopressin recipients and 16 control patients (no desmopressin) were similar in surgical procedure, pump time, platelet count, template bleeding time and amount of bleeding before therapy (p = NS). Compared with the control group, the patients receiving desmopressin (20 micrograms; mean 0.3 micrograms/kg) utilized fewer blood products (29 +/- 19 versus 15 +/- 13 units/patient; p less than 0.05), especially platelets (12 +/- 9 versus 4 +/- 7 units/patient; p = 0.004), while achieving a similarly effective reduction in mediastinal bleeding (4.8- and 4.3-fold, p = 0.001 for both). Severe platelet dysfunction was partially corrected within 1 hour after desmopressin infusion, during which interval no blood products were administered: the template bleeding time shortened (from 17 to 12.5 minutes, p less than 0.05), whereas the platelet count remained unchanged (at 96 +/- 35 and 105 +/- 31 X 10(3)/mm3, p = NS). The plasma levels of two factor VIII components increased: procoagulant activity (VIII:C) from 0.97 +/- 0.43 to 1.52 +/- 0.74 units/ml (p less than 0.05) and von Willebrand factor (VIII:vWF) from 1.28 to 1.78 units/ml (p less than 0.05); these increases correlated with the shortening of the bleeding time (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

A pilot study; desmopressin (DDAVP) in the treatment of deep venous thrombosis

In a pilot study on 9 patients with acute deep venous thrombosis of the leg the fibrinolytic response and the possible thrombolytic effect of desmopressin (DDAVP), when given supplementary to standard heparin treatment, was examined. Six injections of 0.3-0.4 microgram DDAVP/kg b.w. at 12 hours intervals were given. No serious side effects were observed. The fibrinolytic variables that followed showed that plasma levels of t-PA increased significantly and most pronounced after the first injection. Rephlebography 4-7 days after hospitalization showed partial thrombolysis in 7 out of 9 patients. The phlebographic score according to Marder was reduced from 22.7 +/- 12.1 to 18.4 +/- 10.1 (p = 0.018), corresponding to a thrombus size reduction of 19%. No correlation between the level of the fibrinolytic variables measured and the degree of thrombolysis in the individual patients, could be demonstrated in this small number of patients.

DDAVP-induced increases in coagulation factor VIII and von Willebrand factor in the plasma of conscious dogs

Infusion of the vasopressin analogue DDAVP into five normal dogs at doses of 0.1-2.0 micrograms DDAVP per kg body weight induced dose-dependent increases in the plasma content of coagulation factor VIII and von Willebrand factor. Plasma concentrations of von Willebrand factor (determined antigenically as factor VIII-related antigen and functionally as coagglutinin cofactor activity) and coagulation factor VIII were measured immediately before and at 10, 30, and 120 min after 10-min intravenous infusions of DDAVP. The greatest increases in coagulation factor VIII were produced with the 2.0 micrograms/kg dose. Ten minutes after infusion the mean increase in coagulation factor VIII was 32 units/dl (concentrations of all indices were reported relative to concentrations in a standard canine plasma pool, arbitrarily assigned a concentration of 100 units/dl) and this increase did not change significantly throughout the duration of the experiment. At 10 min post-infusion, the mean factor VIII-related antigen concentration increased 81 units/dl (dose = 2.0 micrograms/kg) and did not change significantly for the duration of the experiment. The maximum mean increase in coagglutinin cofactor activity, 141 units/dl, occurred 10 min after infusion (dose = 1.0 microgram/kg). Coagglutinin cofactor activity decreased significantly from peak activity by 120 min post-infusion.

The use of desmopressin in children with coagulation disorders

Hemophilia A, von Willebrand's disease and uremia prolong the bleeding time in affected children. Management of hemorrhage is difficult in these patients, and often requires multiple therapeutic modalities. Desmopressin, a synthetic analog of arginine vasopressin (DDAVP), decreases the bleeding time in patients with these disorders. We describe a case of a child with uremia and spontaneous epistaxis originating from the adenoid. Bleeding was controlled with administration of DDAVP and other measures. DDAVP is effective for the rapid, temporary correction of prolonged bleeding time associated with hemophilia A, von Willebrand's disease or uremia. The use of DDAVP avoids the risks associated with blood component transfusion. DDAVP may be used as a single hemostatic agent in minor surgical procedures, or in combination with other therapeutic modalities in major surgical procedures.

Acquired von Willebrand disease and storage pool disease in chronic myelocytic leukemia

Platelet function was evaluated in 20 patients with chronic myelocytic leukemia (CML), all Ph positive. Seven showed abnormal epinephrine-induced aggregation, while four had impaired both ADP- and collagen-induced aggregation. The platelets of all patients aggregated with arachidonic acid, thus ruling out cyclooxygenase or lipoxygenase deficiency. The intracellular concentrations of ATP and ADP were significantly below normal, and the ratio of ATP/ADP was greater than normal in all 12 patients. ATP released from platelets by Lumi-aggregometer was reduced. In four patients with abnormal ristocetin-induced aggregation, vWF:Ag, RCoF, and FVIII:C were all reduced. No significant inactivation of factor VIII was induced in normal plasma by incubation with patient's plasma. The crossed immunoelectrophoretic analysis revealed that vWF:Ag in these patients was mainly composed of more anodic component as compared with that of normal plasma. The ratio of vWF:Ag/RCoF was significantly greater than normal. A marked increase of factor VIII and a rapid return of vWF:Ag and RCoF to the baseline after the 1-deamino-8-arginine vasopressin (DDAVP) infusion were observed. Transient increase in vWF:Ag after the infusion of DDAVP appeared with less anodic forms and in the same relative proportion as that in normal plasma. The present study shows that in some patients with CML storage pool disease occurs with acquired von Willebrand disease.

The subcutaneous administration of the vasopressin analogue 1-desamino-8-D-arginine vasopressin in patients with von Willebrand's disease and hemophilia

Twenty-one patients suffering from mild von Willebrand's disease (vWd) and patients suffering from mild or moderate hemophilia A received 1-desamino-8-D-arginine vasopressin (DDAVP) (Minirin, Ferring AG) s.c. at a dose of 0.4 microgram/kg body weight. Additionally, two hemophiliacs and 22 patients with vWd received DDAVP i.v. Within the observation period of 3 h Factor (F) VIII:C levels increased 2.4 X baseline levels in hemophiliacs, and the maximal effect was observed 3 h post DDAVP s.c. In patients with vWd post DDAVP s.c. (i.v.) a 2.7 (3.4), 2.1 (1.9) and 2.2 (2.8) fold increase for F VIII: C, F VIIIR:Ag and F VIII:Rcof was observed. In eight patients suffering from vWd with additional F XII deficiency a small and transitory but significant increase of F XII levels was detected post DDAVP s.c. No local or systemic side effects were observed. In five patients with vWd tooth extractions were performed without bleeding complications under DDAVP s.c. treatment. Two patients practiced self-treatment by injecting the drug s.c. at home. We thus conclude that s.c. DDAVP is an effective, reliable, and cost-reducing form of treatment that does not bring with it the risk of transmitting infectious diseases in patients with vWd and hemophilia and that can be administered at home.

Factor VIII-related activities after 1-deamino-8-D-arginine vasopressin in multicentric reticulohistiocytosis

A woman with multicentric reticulohistiocytosis, having symptoms including bleeding and a borderline level of factor VIII, was given an i.v. infusion of DDAVP as a pharmacological test to evaluate the release of factor VIII-related properties from storage sites. The results show a reduced response to DDAVP in the patient in comparison with a normal control subject. This could be due either to a defect in the release of the factor VIII complex after DDAVP or to a reduced synthesis and/or storage capacity by the storage cells.

Platelet aggregation induced by 1-desamino-8-D-arginine vasopressin (DDAVP) in Type IIB von Willebrand's disease

Type IIB von Willebrand's disease is a distinct form of this disorder, in which there are abnormal factor VIII/von Willebrand factor multimers in plasma (but normal multimers in platelets) and heightened interaction between the von Willebrand factor and platelets in the presence of ristocetin. We have found that infusion of desmopressin acetate (1-desamino-8-D-arginine vasopressin [DDAVP]), an agent used in the treatment of von Willebrand's disease, causes platelet aggregation and thrombocytopenia in patients with Type IIB disease. In vitro, platelets in normal plasma and those obtained from patients with Type IIB disease before DDAVP infusion aggregated upon the addition of platelet-poor plasma from Type IIB patients treated with DDAVP. Platelet aggregation was associated with adsorption of multimers of factor VIII/von Willebrand factor onto the platelets and was inhibited by EDTA. We conclude that in Type IIB von Willebrand's disease, DDAVP releases an abnormal factor with platelet-aggregating properties. DDAVP should not be used to treat patients with Type IIB disease, since the presence of platelet aggregates in the circulation may be harmful.

DDAVP: does the drug have a direct effect on the vessel wall?

Evidence is presented that 1-deamino-8-d-arginine vasopressin (DDAVP), a vasopressin analog, has a direct effect on isolated vessel segments. The most significant finding is increased platelet adhesion and spreading at injury sites. An isologous human umbilical vein perfusion model was used to compare effects of DDAVP with those of epinephrine or zero drug controls. Scanning electron microscopy, in conjunction with morphometry, permitted quantification of platelet adhesion to subendothelium exposed by minimal injury in the model. In addition, umbilical vein effluents were tested for levels of factor VIII moieties (F VIII:C, F VIII:Rag, F VIII:RCof) and the prostanoids, 6 keto PGF1 alpha (stable metabolite of prostacyclin) and TXB2 (stable metabolite of thromboxane A2. Only F VIII:C from DDAVP treated segments was significantly (p less than 0.01) changed from controls.

Deamino-8-D-arginine vasopressin shortens the bleeding time in uremia

In a randomized double-blind cross-over trial we gave either 1-deamino-8-D-arginine vasopressin or placebo to 12 patients with uremia, hemorrhagic tendencies, and prolonged bleeding times. After vasopressin infusion, all patients had shortened bleeding times, with the effect lasting for at least four hours in most cases. Platelet count, platelet cyclic AMP levels, platelet retention on glass beads, plasma fibronectin, serum thromboxane B2 and residual prothrombin, hematocrit, and plasma osmolarity were unchanged after vasopressin. A consistent post-infusion increase in factor VIII coagulant activity and, to a lesser extent, in factor VIII-related antigen and ristocetin cofactor accompanied the shortening of bleeding time. In addition, vasopressin induced the appearance in plasma of larger von Willebrand-factor multimers than those present in the resting state. The compound was given to nine additional patients with acute or chronic renal failure and prolonged bleeding times, before major surgery or renal biopsy. In these patients, shortening of the bleeding time was associated with normal hemostasis. Our findings indicate that 1-deamino-8-D-arginine vasopressin can be used for temporary correction of bleeding time and may prevent surgical bleeding in patients with uremia.

Comparison of the plasminogen activator activity of superficial hand and foot veins

The plasminogen activator (PA) activity in superficial hand and foot veins was determined with a fibrin slide technique in 68 patients (46 with and 22 without thrombosis). The activity in the hand veins was identical to that of the foot veins in 57% of the patients and higher in 38%. There was a correlation between activity in hand and foot veins in patients with and without thrombosis. Thus, biopsy specimens from superficial hand veins can be used for assessing the PA activity in patients with leg thrombosis.

The effect of intranasal DDAVP on coagulation and fibrinolytic activity in normal persons

DDAVP (1-desamino-8-D-arginine vasopressin) was administered intranasally to 20 normal persons and blood was collected at various intervals up to 72 h. Plasma concentrations of VIII:C, VIIIR:Ag and fibrinolytic activity were increased by DDAVP with peak levels observed 1 h after the administration. Factors V, IX, XI, XII, XIII, P-APT time, platelets, platelet factor 3, P&P, AT III, alpha 2AP, fibrinogen and FDP were unchanged by the treatment. No side effects or changes in plasma Na or osmolality were observed. The present data demonstrate the selectivity of the effect of DDAVP on the coagulation system and points towards the possibility of using DDAVP in blood donors to increase plasma contents of factor VIII.