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Aim Evidence suggests beneficial metabolic effects of the nonapeptide hormone, arginine vasopressin (AVP), on metabolism, as also observed recently with the closely related oxytocin peptide. Materials and methods In the current study we have exchanged selected amino acids at position 3 and 8 of AVP, namely phenylalanine and arginine, with those of oxytocin to generate novel analogues with altered receptor selectivity. Secondary modification by N-terminal acetylation was used to impart stability to circulating endopeptidases. Analogues were screened for degradation, bioactivity in rodent/human clonal beta-cells and primary murine islets together evaluation of receptor activation profile. Results Analogue Ac3IV, which lacked effects at V2 receptors responsible for modulation of fluid balance, was selected as the lead compound for assessment of antidiabetic efficacy in high fat fed (HFF) mice. Twice daily administration of Ac3IV, or the gold-standard control exendin-4, for 22 days reduced energy intake as well as body weight and fat content. Both interventions decreased circulating glucose levels, enhanced insulin sensitivity and substantially improved glucose tolerance and related insulin secretion in response to an intraperitoneal or oral glucose challenge. The peptides decreased total- and increased HDL-cholesterol, but only Ac3IV decreased LDL-cholesterol, triglyceride and non-fasting glucagon concentrations. Elevations of islet and beta cell areas were partially reversed, accompanied by suppressed islet cell proliferation, decreased beta-cell apoptosis and, in the case of exendin-4, also decreased alpha-cell apoptosis. Conclusion AVP-based therapies that exclusively target V1a and V1b receptors may have significant therapeutic potential for the treatment of obesity and related diabetes, that merits further clinical exploration. This article is protected by copyright. All rights reserved.

Terlipressin is a synthetic vasopressin analogue used in the treatment of cirrhotic patients with variceal bleeding and hepatorenal syndrome. Side effects associated with terlipressin are usually mild but some rare serious complications can also be seen. Terlipressin induced skin ischemia is one such serious complication. We report a case of 57-year-old lady, a case of chronic alcoholic liver disease presented with variceal bleeding. Patient was given bolus injection terlipressin every 4 hour and patient developed skin ischemia within 48 hours of terlipressin administration. Skin ischemic changes showed marked improvement after stoppage of terlipressin. Treating clinicians should be more vigilant about this rare adverse effect of terlipressin. Early recognition and treatment of the ischemic skin complication gives a better outcome. How to cite this article: Kumar N, Bohania N, Kumar S. Terlipressin Induced Skin Ischemia: A Case Report. J Adv Res Med 2019; 6(4): 10-12. DOI: https://doi.org/10.24321/2349.7181.201918

The vasopressin analogue desmopressin (desamino-d-arginine8 vasopressin, dDAVP, 1) is a potent vasopressin 2 (V2) receptor (V2R) agonist approved in many countries for the treatment of diabetes insipidus, primary nocturnal enuresis, nocturia, and coagulation disorders. Since 1 is primarily excreted via the kidneys, an age-related decline in kidney function leads to slower elimination, prolonged antidiuresis, and hyponatremia. In search of novel, potent, selective, and short-acting peptidic V2R agonists, we synthesized a series of C-terminally truncated analogues of [Val4]dDAVP, 2, modified in positions 2, 3, and 7 and/or at the disulfide bridge. The peptides were evaluated for in vitro potency at the human V2 receptor, selectivity versus the related receptors (human vasopressin 1a receptor, human vasopressin 1b receptor, and human oxytocin receptor), and pharmacokinetic profiles in rodents and other higher species. The truncated analogues show excellent potency at the V2R, increased systemic clearance, and shorter half-life in rats. Two compounds 19 (c(Bua-Cpa-Thi-Val-Asn-Cys)-Pro-Agm) and 38 (c(Bua-Cpa-Thi-Val-Asn-Cys)-Pro-d-Arg-NEt2) have been selected for clinical development for nocturia.

Background: Terlipressin is used as pharmacological treatment for variceal bleeding. The drug’s physiological effect favours hyponatremia, and rapid changes in plasma sodium (PNa) may cause brain injury. Cirrhosis patients seem to be largely protected against this effect but patients without cirrhosis may not be so. Objective: The objective of this study was to examine whether terlipressin treatment of patients without cirrhosis leads to more serious fluctuations in PNa than in cirrhosis. Methods: In a retrospective cohort design, during a 39-month period, 11 patients with prehepatic portal hypertension and no cirrhosis and 134 patients with cirrhosis received a minimum cumulative terlipressin dose of 4mg during at least 24 hours for variceal bleeding. The groups’ PNa changes were compared. Results: During terlipressin, the non-cirrhotic patients developed a greater reduction in PNa [mean 8.3 (95% confidence interval (CI) 1.9–14.6) vs. 1.8 (1.0–2.7) mmol/l; p=0.048], a lower nadir PNa [129 (123–135) vs. 133 (132–134) mmol/l; p=0.06], and within 48 hours after terlipressin a greater increase in PNa [12.6 (3.4–21.7) vs. 2.3 (1.5–3.0) mmol/l; p=0.03]. Severe (>10 mmol/l change) hyponatriemia or PNa rebound were seen in 27% of these patients but in only 4% of those with cirrhosis (p=0.02). One non-cirrhotic patient developed permanent brain damage. Conclusion: Terlipressin treatment of bleeding varices carries a high risk of potentially dangerous PNa fluctuations in patients with non-cirrhotic prehepatic portal hypertension.

We describe a three-year-old boy who had a growth and psychomotor retardation associated with inappropriate lack of thirst and vasopressin secretion in the presence of chronic plasma hyperosmolarity. Computed brain tomography revealed bilateral supratentorial sub-ependymal and cortical calcifications. Dissociation in the plasma vasopressin response to osmotic change was demonstrated in this patient. Treatment with a vasopressin analogue, desamino-D-arginine vasopressin (DDAVP) and forced intake of water restored plasma osmolality and serum sodium levels to normal.Keywords: Brain calcifications, child, hypodipsic hypernatremia syndrome

Extracellular vesicles (ECVs) facilitate intercellular communication along the nephron, with the potential to change the function of the recipient cell. However, it is not known whether this is a regulated process analogous to other signaling systems. We investigated the potential hormonal regulation of ECV transfer and report that desmopressin, a vasopressin analogue, stimulated the uptake of fluorescently loaded ECVs into a kidney collecting duct cell line (mCCDC11) and into primary cells. Exposure of mCCDC11 cells to ECVs isolated from cells overexpressing microRNA-503 led to downregulated expression of microRNA-503 target genes, but only in the presence of desmopressin. Mechanistically, ECV entry into mCCDC11 cells required cAMP production, was reduced by inhibiting dynamin, and was selective for ECVs from kidney tubular cells. In vivo, we measured the urinary excretion and tissue uptake of fluorescently loaded ECVs delivered systemically to mice before and after administration of the vasopressin V2 receptor antagonist tolvaptan. In control-treated mice, we recovered 2.5% of administered ECVs in the urine; tolvaptan increased recovery five-fold and reduced ECV deposition in kidney tissue. Furthermore, in a patient with central diabetes insipidus, desmopressin reduced the excretion of ECVs derived from glomerular and proximal tubular cells. These data are consistent with vasopressin-regulated uptake of ECVs in vivo. We conclude that ECV uptake is a specific and regulated process. Physiologically, ECVs are a new mechanism of intercellular communication; therapeutically, ECVs may be a vehicle by which RNA therapy could be targeted to specific cells for the treatment of kidney disease.

This chapter discusses inherited disorders of platelet function. Patients with inherited disorders of platelet function display mucocutaneous bleeding of variable severity and excessive hemorrhage after surgery or trauma. The diagnostic laboratory assessment appropriate for the evaluation of suspected inherited defects of platelet function should be based on a two-step diagnostic strategy: in the first step, screening tests that essentially based on the evaluation of the ability of platelets to aggregate and secrete the contents of their cytoplasmic granules help raising a diagnostic hypothesis, which should then be tested in the second step, which is based on the use of specific tests. The first step should include: complete blood cell count, examination of the peripheral blood smear and assessment of platelet aggregation and secretion. The second step includes specific tests (e.g., flow cytometry, Western blotting, DNA analysis). Platelet transfusions should be used only to treat severe bleeding episodes. Recombinant Factor VIIa can be used in patients with severe bleeding episodes who do not respond to platelet transfusion because of alloimmunization. Additional treatment options include fibrinolytic inhibitors (e.g., tranexamic acid) and the vasopressin analogue desmopressin (DDAVP).

For a new formulation of a drug, only pharmacokinetic bioequivalence with the original formulation has to be demonstrated in healthy, young adults. However, “children are not small adults,” and to guarantee a safe and effective treatment, age-adapted drug development is required. Desmopressin, a vasopressin analogue prescribed for nocturnal enuresis in children, was studied as an example formulation first developed in adults and then extrapolated to a pediatric indication. Population pharmacokinetic and pharmacodynamic modeling was used to analyze previously published desmopressin data of 18 children suffering from nocturnal enuresis. The main objective was the comparison of the therapeutic equivalence of two desmopressin formulations: tablet and lyophilisate. The measurements for pharmacokinetics and pharmacodynamics were respectively plasma desmopressin concentration and urine osmolality and diuresis. The half maximal inhibitory concentration for inhibition of urine production was 0.7 pg/mL lower for the lyophilisate than for the tablet. The effect of formulation on the half maximal inhibitory concentration seems to suggest that the 120-μg lyophilisate has a more pronounced effect on the urine volume and osmolality than the 200-μg tablet, even when the same exposure is achieved. A new indirect response model for desmopressin was constructed and validated, using a previously built pharmacokinetic model and additional pharmacodynamic data. In order to draw solid conclusions regarding the efficacy and safety of desmopressin in children, pharmacokinetics and pharmacodynamics data should be analyzed together. This study adds proof to potential differences in pediatric and adult pharmacokinetic and pharmacodynamic properties of desmopressin and exemplifies the need for pediatric clinical trials, not only for every new drug but also for every new formulation.

Background Aquaporins (AQPs) are a family of proteins that can act as water channels. Regulation of AQPs is critical to osmoregulation and the maintenance of body water homeostasis. Eight AQPs are expressed in the kidney of which five have been shown to play a role in body water balance; AQP1, AQP2, AQP3, AQP4 and AQP7. AQP2 in particular is regulated by vasopressin. Scope of review This review summarizes our current knowledge of the underlying mechanisms of various water balance disorders and their treatment strategies. Major conclusions Dysfunctions of AQPs are involved in disorders associated with disturbed water homeostasis. Hyponatremia with increased AQP levels can be caused by diseases with low effective circulating blood volume, such as congestive heart failure, or osmoregulation disorders such as the syndrome of inappropriate secretion of antidiuretic hormone. Treatment consists of fluid restriction, demeclocycline and vasopressin type-2 receptor antagonists. Decreased AQP levels can lead to diabetes insipidus (DI), characterized by polyuria and polydipsia. In central DI, vasopressin production is impaired, while in gestational DI, levels of the vasopressin-degrading enzyme vasopressinase are abnormally increased. Treatment consists of the vasopressin analogue dDAVP. Nephrogenic DI is caused by the inability of the kidney to respond to vasopressin and can be congenital, but is most commonly acquired, usually due to lithium therapy. Treatment consists of sufficient fluid supply, low-solute diet and diuretics. General significance In recent years, our understanding of the underlying mechanisms of water balance disorders has increased enormously, which has opened up several possible new treatment strategies. This article is part of a Special Issue entitled Aquaporins.

Stimulation with the vasopressin analogue desmopressin (DDAVP) of extrarenal arginine vasopressin (AVP) V2-receptors in endothelial cells and possible in platelets increases the circulating levels of coagulation factor VIII (FVIII), von Willebrand factor (VWF) and tissue plasminogen activator (t-PA). The purpose of this paper is to provide an updated review of current information on the efficacy and safety of DDAVP in the treatment of haemophilia, von Willebrand disease (VWD), uremia, liver cirrhosis, and in congenital or drug-induced platelet dysfunction--under surgical or non-surgical conditions. In summary, desmopressin is an effective haemostatic drug that when administered i.v., s.c. or intranasally increases plasma levels of FVIII and VWF 2-6 times and improves platelet function. It has a proven haemostatic efficacy in mild haemophilia A and VWD as well as in uremia, liver cirrhosis and in congenital and acquired, drug induced platelet dysfunction. Desmopressin has few side effects but observation is advised in small children and elderly.

In this paper, we apply the results on both the model AMSAA Crow projection model and Reliability growth potential effects of vasopressin to examine the relation between nocturnal vasopressin release and response to treatment with the vasopressin analogue 1-desamino-8-D-Arginine Vasopressin (DDAVP) in children with primary mono symptomatic nocturnal enuresis. In this application the ability to respond to DDAVP is related to endogenous AVP production and is influenced by neuronal patterning in early infancy. The result concludes that ACPM of MTBF projection is estimated of the system failure intensity.ρ GP is the growth potential of Mean time between failure of AVP release according to the result in the estimated growth potential failure intensity , the estimate of the system MTBF growth potential. Thus the ACPM Projection for the system failure intensity, based onβ , the corresponding MTBF Projection value is nearly equal to the Projected system failure intensity based onβ m , the corresponding MTBF Projection values.

Terlipressin is a vasopressin analogue that is widely used in the treatment of hepatorenal syndrome or variceal bleeding. Because it acts mainly on splanchnic vessels, terlipressin has a lower incidence of severe ischemic complications than does vasopressin. However, it can still lead to serious complications such as myocardial infarction, skin necrosis, or bowel ischemia. Herein we report a case of severe ischemic bowel necrosis in a 46-year-old cirrhotic patient treated with terlipressin. Although the patient received bowel resection, death occurred due to ongoing hypotension and metabolic acidosis. Attention should be paid to patients complaining of abdominal pain during treatment with terlipressin.

Terlipressin is a vasopressin analogue used in esophageal variceal bleeding and hepatorenal syndrome management. It is a safe drug with mild secondary effects. However, potentially serious ischemic complications may occur, such as cutaneous necrosis. It is useful to recognize these events early, in order to withdraw terlipressin and introduce other adjuvant drugs if needed. We report a detailed case of cutaneous necrosis secondary to terlipressin administration and present a case review of patients, describing their characteristics, risk factors, lesion locations, doses, methods of administration and possible treatments.

Terlipressin is a vasopressin analogue used for its vasoconstrictor effect in the treatment of variceal bleeding. Despite its good safety profile compared to vasopressin, some adverse reactions may occur during its use – e.g. hyponatremia. We describe a case of a cirrhotic patient with active variceal bleeding treated during two separate hospitalizations with terlipressin. In both drug treatment periods, severe laboratory hyponatremia developed. After terlipressin discontinuation, mineral disbalance corrected rapidly. Positive dechallenge and rechallenge corresponding to the drug administration schedule confirms the causality between terlipressin administration and hyponatremia. Hyponatremia was preceded with substantial fluid retention in both episodes. In this case report we want to highlight the need for fluid balance monitoring immediately after first terlipressin dose, which may individually predict the patient risk for the development of hyponatremia as other risk factors have rather limited predictive value in real clinical settings.

Background and aims The vasopressin analogue desmopressin has demonstrated efficacy in decreasing bleeding time by increasing the circulating levels of coagulation factor VIII and von Willebrand factor, but also by direct effects on platelets. Previous studies have demonstrated contrasting results regarding the effect of desmopressin on platelets in vitro. The aim of this study was to investigate the dose-response effects of in vitro desmopressin in whole blood. Our hypothesis was that desmopressin could increase platelet function in anticoagulated whole blood being stored up to 4 hours. Methods Desmopressin was administered with up to four different concentrations to venous whole blood, sampled with standard vacutainer tubes from 10 healthy volunteers after consent. Platelet function was analyzed with three different point-of-care techniques: Multiplate platelet aggregometry with adenosine diphosphate, collagen, thrombin receptor activating peptide-6, ristocetin and arachidonic acid agonists, tissue factor-activated thromboelastometry and Sonoclot glass bead viscoelastic coagulation tests at baseline and 4 hours later using different activator reagents. Results Thromboelastometry and Sonoclot did not show any significant change between baseline and 4 h later. A significant decrease in area under curve (AUC) could be seen with the Multiplate between baseline and after 4 h. Desmopressin did not improve any of these tests at baseline or during a 4 h storage and incubation period. Conclusion In vitro administered desmopressin could not increase normal platelet function or coagulation being measured with thromboelastometry and Sonoclot. Multiplate indicated decreased platelet aggregation over time, without any effect of in vitro added desmopressin.

Congenital abnormalities of platelet function disorder (PFD) are associated with the heightened risk for bleeding. Typically, patients with PFDs have mucocutaneous bleeding of variable severity and excessive hemorrhage after surgery or trauma. The diagnostic laboratory assessment appropriate for the evaluation of suspected inherited PFD should be based on a two-step diagnostic strategy: the first step, based on screening tests, helps raising a diagnostic hypothesis, which should then be tested in the second step, which is based on the use of specific tests. The first step should include: complete blood cell count, examination of the peripheral blood smear, and assessment of platelet aggregation. Although light transmission aggregometry (LTA) is the most widely used platelet function test, it is relatively insensitive to defects of platelet secretion; for this reason, laboratory tests that measure platelet aggregation and secretion simultaneously, such as lumi-aggregometry, should be preferred to traditional LTA. The second step includes specific tests (e.g., flow cytometry, Western blotting, DNA analysis). Platelet transfusions should be used only to treat severe bleeding episodes. Recombinant Factor VIIa can be used in patients with severe bleeding episodes who do not respond to platelet transfusion because of alloimmunization. Fibrinolytic inhibitors or the vasopressin analogue desmopressin (DDAVP) should be used in all other circumstances.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Desmopressin is a known haemostatic agent and is also being used, albeit at lower doses, during the diagnostic work-up of Cushing's syndrome, a condition characterized by excess cortisol concentrations and frequent thromboembolic events. No study has yet evaluated whether admininistration of desmopressin for diagnostic purposes induces significant, adverse changes in endothelial cell markers in these patients. WHAT THIS STUDY ADDS • Administration of desmopressin to patients with Cushing's disease induces changes in endothelial cell markers comparable with those observed in obese and normal weight subjects. It follows, that desmopressin testing does not induce disease-specific untoward changes in coagulatory markers in patients with endogenous hypercortisolism and its use in this context appears safe. AIMS Desmopressin, a vasopressin analogue, is used for various clinical purposes, including haemostasis and, in recent times, the diagnostic work-up of patients with Cushing's syndrome, a condition associated with a known prothrombotic profile. We decided to evaluate whether and to what extent a diagnostic dose of desmopressin induces significant changes in endothelial parameters in patients with Cushing's disease (CD) and obese and normal weight controls. METHODS Twelve patients with CD, 10 obese and five normal weight controls were studied. Von Willebrand antigen (VWF : Ag), tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were measured at baseline and up to 4 h after 10 µg desmopressin i.v. RESULTS Desmopressin 10 µg transiently increased VWF : Ag and t-PA and decreased PAI-1 in all subjects. The magnitude of the VWF : Ag and t-PA increases after desmopressin was comparable in the three groups (VWF : Ag peak-to-basal ratio 1.9 ± 0.17, 1.5 ± 0.11 and 1.8 ± 0.13 and t-PA peak-to-basal ratio 1.6 ± 0.18, 1.6 ± 0.20 and 1.8 ± 0.24 for CD, obese and controls, respectively, all NS). The PAI-1 decrease observed in patients with CD was comparable with obese (0.7 ± 0.07 and 0.6 ± 0.09, NS) and controls (0.7 ± 0.07 vs. 0.4 ± 0.09, P= 0.08). CONCLUSIONS Administration of desmopressin to patients with CD for diagnostic purposes induces a transitory increase in VWF : Ag counterbalanced by a decrease in PAI-1 and increase in t-PA. The magnitude of these changes is largely comparable with that observed in obese and normal weight controls. Our data show that testing with desmopressin does not induce disease-specific changes in endothelial markers in patients with CD.

The renal concentrating ability was studied in 11 subjects by means of 14-16 hours of fluid deprivations, alone and in combination with the vasopressin analogue desmopressin. The effect of desmopressin without fluid deprivation on urinary osmolality was also studied. The combination of desmopressin and fluid deprivation was not superior to fluid deprivation alone for the production of concentrated urine. Desmopressin alone was inferior to the other two methods. No difference in renal concentrating ability could be demonstrated after 14 hours of fluid deprivation, when comparing 118 subjects exposed to various organic solvents with 48 controls.

Type IIB von Willebrand's disease (vWD) is a distinct form of this disorder in which the largest multimers of the von Willebrand factor (vWF) are lacking in plasma but present in platelets. When the vasopressin analogue, 1-deamino-8-D-arginine vasopressin (DDAVP), is given to patients with type IIB vWD, an abnormal vWF is released to plasma. This vWF causes thrombocytopenia in vivo and platelet aggregation in vitro. Aggregation occurs in the plasma milieu and thus at physiological fibrinogen concentration. In this study we demonstrate that IIB post-DDAVP vWF aggregated only metabolically active platelets. The platelet aggregation was completely inhibited by EDTA and PGE1, and either inhibited or greatly weakened by ASA, demonstrating the role of divalent cations and thromboxane A2 formation. In spite of inhibiting platelet aggregation, EDTA, PGE1 and ASA did not prevent platelet binding of IIB post-DDAVP vWF. An antiserum against GP Ib made normal platelets less responsive to the IIB vWF although neither platelet aggregation nor vWF binding were completely prevented. The aggregation was fibrinogen-dependent and platelets from patients with Glanzmann's thrombasthenia were unresponsive. The studies provide evidence that IIB post-DDAVP vWF is bound to unstimulated platelets and that the interaction between vWF and platelets in type IIB vWD is different from ristocetin-induced as well as thrombin- and epinephrine-induced binding to platelets of normal vWF.

Nalpha-triglycyl-(8-lysine)-vasopressin (TGLVP) was administered intravenously to pregnant guinea pigs and the effect on regional blood flow examined by the radioactive microsphere technique. A dose of 10 mug/kg TGLVP caused an elevation of the mean arterial blood pressure, from 6.4 to 11.1 kPa, a significant reduction in blood flow to the gut, skin and skeletal muscle and a significant increase in blood flow to the spleen. The number of 15 +/- 5 mum microspheres reaching the lungs diminished significantly after 10 mug/kg TGLVP, indicating that this dose constricted arterio-venous short circuits in the systemic circulation. There was also a decrease in blood flow to the urogenital tract, including the placentae. When 3 mug/kg TGLVP was injected, the mean arterial blood pressure rose from 6.5 to 8.7 kPa and there was no longer any consistent effect on maternal placental blood flow. It is suggested that pregnancy constitutes a contraindication for TGLVP, since a reduction in uterine and maternal placental blood flow might occur with clinically relevant doses.

In a double-blind controlled trial the possible prophylactic effect of intranasally applicated DDAVP (1-desamino-8-arginine vasopressin, Minurin)--a synthetic analogue of vasopressin--is evaluated regarding the incidence of headache following lumbar puncture (LBP) in 51 patients and following pneumoencephalography (PEG) in 28 patients. DDAVP had no statistically significant effect on the incidence of headache or on the consumption of analgesics in the DDAVP-versus placebo groups (minimal relevant difference = 50%, 2 alpha = 0.05, beta = 0.50).

Summary. 1-deamino-8-D-arginine-vasopressin (DDAVP), was used in a wide spectrum of clinical situations employing two different dosages (0.3 and 0.4 μg/kg b. w.) for the management of 43 patients with factor VIII deficiences–mild and moderate haemophilia A and von Willebrand's disease (vWD). In most instances, the drug was given in association with antifibrinolytics. Twenty-five dental extractions were carried out with two different protocols: one based upon a single infusion and the other based upon three infusions. Bleeding occurred in three patients regardless of the protocol used. The vasopressin analogue promptly stopped bleeding in 12 ‘spontaneous’ open bleeds (haematuria, epistaxis, menometrorrhagia, gum bleeding) and it appears to be also effective in closed bleeds. DDAVP was used to minimize blood loss during surgical interventions and to avoid haemorrhage in the postoperative period. Nine surgical procedures were carried out in six vWD patients and three haemophiliacs. Bleeding occurred late in the postoperative period on one occasion only. No difference was demonstrated between the two doses of the drug either in terms of clinical benefit or rise of factor VIII coagulant activity. The efficacy of DDAVP and the absence of side-effects make this vasopressin analogue worthy of consideration as a reliable alternative to factor VIII concentrates in a wide variety of clinical situations.

The synthetic vasopressin analogue, terlipressin, is being increasingly used to treat catecholamine-resistant hypotension in septic shock and other conditions. While terlipressin holds some theoretical and anecdotal advantages over vasopressin, this has not been formally tested in prospective randomised trials. This review analyses the published literature and makes comparisons, where possible, between vasopressin and terlipressin.

International audience; We report the discovery of conopressin-T, a novel bioactive peptide isolated from Conus tulipa venom. Conopressin-T belongs to the vasopressin-like peptide family and displays high sequence homology to the mammalian hormone oxytocin (OT) and to vasotocin, the endogenous vasopressin analogue found in teleost fish, the cone snail's prey. Conopressin-T was found to act as a selective antagonist at the human V1a receptor. All peptides in this family contain two conserved amino acids within the exocyclic tripeptide (Pro7 and Gly9), which are replaced with Leu7 and Val9 in conopressin-T. Whereas conopressin-T binds only to OT and V1a receptors, an L7P analogue had increased affinity for the V1a receptor and weak V2 receptor binding. Surprisingly, replacing Gly9 with Val9 in OT and vasopressin revealed that this position can function as an agonist/antagonist switch at the V1a receptor. NMR structures of both conopressin-T and L7P analogue revealed a marked difference in the orientation of the exocyclic tripeptide that may serve as templates for the design of novel ligands with enhanced affinity for the V1a receptor.

The synthetic vasopressin analogue (1-deamino-8-D-arginine-vasopressin) increases plasma concentration of factor VIII and von Willebrand factor in normal subjects and patients with mild haemophilia A and von Willebrand disease. Since its first clinical use in 1977, desmopressin has become the treatment of choice for patients with haemophilia A and factor VIII coagulant activity (FVIII:C) > 5% and has spared several patients the risk of acquiring blood-borne viral infections due to the use of non-virally inactivated plasma-derived FVIII concentrates. An average two to sixfolds FVIII:C increase is typically observed in most patients and return to baseline occurs usually within 8 hours. Several clinical studies have demonstrated the clinical efficacy and safety of desmopressin and the availability of concentrated formulation for subcutaneous injection and of a nasal spray has paved the way to home-treatment. However, overall it appears that haemophilic children may have a lower rate of biologic response compared to adults and a minority of adult patients are not able to attain clinically useful FVIII:C levels post-desmopressin administration. Thus, in every patient with haemophilia A likely to be treated or candidate to an elective invasive procedure, a test-infusion/injection should be carried out to assess the future usefulness of the compound.

Desmopressin is a synthetic vasopressin analogue mainly used in treatment of diabetes insipidus and nocturia. Studies in rats have revealed a sex difference in the response to a vasopressin infusion, which was diminished after treatment with an NSAID. This study was performed in man to investigate the influence of sex and concomitant treatment of piroxicam on the pharmacokinetics and dynamics of desmopressin, and to validate a previously described indirect response model. Eight healthy males and eight healthy females participated in the trial, which was conducted in a pharmacokinetic (PK) part followed by a pharmacodynamic (PD) part. Desmopressin was administered intravenously as a single dose (PK = dose 2 μg, PD = dose 0.2 μg). Piroxicam was administered to achieve steady state. The pharmacokinetic parameters of desmopressin were estimated and calculated by means of two-compartmental analysis. In the dynamic part a study design based on an oral hydration model was used. Parameters for urine flow and urine osmolality were estimated. Individual estimates of the pharmacokinetic parameters served as input to the indirect response model that subsequently was fitted to urine osmolality data. The pharmacokinetics of desmopressin after a fixed bolus injection was neither influenced by piroxicam nor sex of the subject. The pharmacodynamics of desmopressin showed a sex difference where females exhibited a more pronounced antidiuretic effect than males, which was statistically significant when the effects were submaximal (>4.5 h after dose). The sex differences were diminished after pre-treatment with piroxicam, indicating a prostaglandin PGE2-mediated mechanism. The indirect response model was confirmed, although the modelling could not distinguish a sex difference, indicating a limitation of this model compared with traditional descriptive statistics.

OREBP (osmotic response element-binding protein), also called TonEBP or NFAT5, is thought to induce the expression of genes that increase the accumulation of organic osmolytes to protect cells against a hypertonic environment. To investigate the consequences of lacking OREBP activity, transgenic (Tg) mice that overexpress OREBPdn (dominant negative form of OREBP) specifically in the epithelial cells of the renal collecting tubules were generated. These mice showed impairment in their urine concentrating mechanism, most likely due to reduced expression of the aquaporin AQP2 and the urea transporter UT-A1 and UT-A2 mRNAs. When deprived of water or after the administration of a vasopressin analogue, urine osmolality of the Tg mice was significantly increased but not to the same extent as that of the wild type mice. The expression of AQP2 and UT-A1, but not UT-A2 mRNAs, was increased to the same level as that of the wild type mice in the water deprivation state, indicating that the vasopressin regulatory mechanism was not affected by OREBPdn. These data indicate that in addition to vasopressin, OREBP is another essential regulator of the urine concentrating mechanism. Furthermore, the OREBPdn Tg mice developed progressive hydronephrosis soon after weaning, confirming the osmoprotective function of OREBP implicated by the in vitro experiments.

History and clinical findings A 78-year-old woman was admitted to the intensive care unit 9 hours after ingestion of 2 g of isosorbitmononitrate, 430 mg of amlodipine, 250 mg of benazepril and 600 mg of mirtazapin in suicidal intent. Investigations Clinical findings and invasive monitoring showed signs of a hyperdynamic hemodynamic cardiovascular failure caused by toxic vasodilatation. Treatment and course Despite of primary detoxication, intravenous volume infusion with calcium gluconate, glucagon and naloxone and administration (norepinephrine up to 2 micro g/kg/min) no hemodynamic stabilization was achieved. Only when the vasopressin-analogue argipressin was given peripheral vasodilatation was overcome and hemodynamic stabilization resulted. 10 hours after discontinuing argipressin and norepinephrine the patient developed a mesenteric ischemia, and she finally died on the third day after admission. Conclusion In circulatory shock due to toxic vasodilatation the use of vasopressin analogue argipressin can be helpful as an ultima therapeutic measure in catecholamine refractory shock caused by vasodilatation. Attention must be paid to overwhelming vasoconstrictor effects resulting in mesenteric ischemia.

In recent years, the use of vasopressin analogues in the treatment of hepatorenal syndrome has become an effective therapeutic strategy leading to improved survival and often allowing the completion of liver transplantation. Terlipressin, in particular, has proven to be safe and effective. Due to the limited number of patients treated so far, it is, however, difficult to draw any definite conclusions on the optimal dosage and on the occurrence of side-effects in these patients. The case is reported of an ascitic cirrhotic patient who developed spontaneous bacterial peritonitis followed by a type-I hepatorenal syndrome. Treatment with terlipressin boluses (0.5 mg/4 h) associated with albumin infusion was then started. The course of the disease was monitored by clinical and laboratory means. After 10 boluses of terlipressin, rectorrhagia and severe ischaemic complications involving the skin of the abdomen, lower limbs, scrotus, and penis, occurred. These ischaemic complications improved after terlipressin withdrawal, while renal failure evolved leading to the patient's death. This case report shows that, in patients with type-I hepatorenal syndrome, the use of terlipressin, even at low dosages, may induce life-threatening ischaemic complications and, moreover, suggests that the recent occurrence of spontaneous bacterial peritonitis, even if properly treated, may significantly increase the risk of major ischaemic complications.

Replacement therapy with blood products has long been the only available therapeutic option for patients with bleeding disorders. Plasma-derived cryoprecipitate and factor (F) VIII concentrates, which have been used for hemophilia A patients, involve the risk of transmitting blood-borne diseases. Both plasma-derived and recombinant FVIII concentrates are expensive, and there is a global shortage. The synthetic vasopressin analogue desmopressin acetate (1-deamino-[8-D-arginine]-vasopressin, DDAVP) increases plasma concentrations of coagulation FVIII and von Willebrand factor (vWF) two fold to six fold through endogenous release. The drug is an attractive therapeutic alternative because it carries no risk of transmission of infectious diseases. Desmopressin is today a widely used hemostatic agent not only in patients with mild hemophilia A or von Willebrand disease (vWD) but also in those with congenital or acquired platelet dysfunction. There is a long clinical experience with the drug because it has been used for prevention of bleedings in connection with invasive procedures and for treatment of bleedings since the mid-1970s. Not all hemophilia A patients can be treated. The clinical usefulness depends on the postdesmopressin plasma concentration of FVIII, which in turn depends on the patient's basal FVIII level. Therefore, a test dose is recommended in candidate patients. In general, only the mildest hemophilia A patients respond sufficiently. Optimal hemostatic effect is achieved with a dosage of 0.3 microg/kg given intravenously. An intranasal desmopressin spray is suitable for the home treatment.

The vasopressin analogue desmopressin (dDAVP, 1) is a potent V2 receptor agonist that also activates the related V1b receptor [1]. dDAVP is approved in many countries for the treatment of diabetes insipidus, primary nocturnal enuresis, nocturia, and coagulation disorders including hemophilia A and von Willebrand’s disease. In search of novel, potent, selective and pharmacologically useful peptidic V2R agonists, we synthesized a series of C-terminally truncated [Val4]dDAVP (2) [2] analogs modified in positions 2, 3, 7 and/or at the disulfide bridge. The peptides were evaluated for in vitro potency at the humanV2 receptor (hV2R) and selectivity versus related receptors (hV1aR, hV1bR, hOTR). Here we present comprehensive in vitro data for the new compounds and describe synthetic methods used to prepare the analogues.

Background and Aims: The neurological control of bladder function and the ability to be dry at night involves not only the acquisition of normal daytime control, but also the establishment of a circadian rhythm in vasopressin release and the ability to arouse to a full bladder during sleep. We postulated that in some children there might be a delay in maturation of the normal neurological pathways involved in establishment of nocturnal continence and examined this by using a specific neuropsychological test.\ud \ud Methods: Children attending an established nocturnal enuresis clinic were examined using the Rey–Osterrieth test to assess the presence or absence of boundary errors in both copy and memory reproductions. The results of the test were scored independently and blind to the response to treatment with the vasopressin analogue DDAVP.\ud \ud Results: A significant association was found between boundary type errors and response to DDAVP, with non-responders making significantly more errors. No child with three or more errors responded to DDAVP. Using this test, the ability to predict response to treatment was 70%.\ud \ud Conclusions: It is postulated that the Rey–Osterrieth test, through the presence or absence of boundary errors, reflects a delay in maturation and/or a disorganisation of the retinal-hypothalamic-cortical pathways in the brain. The association previously described with growth hormone neurosecretory dysfunction syndrome would be compatible with this.

In a 10-year-old castrated male shorthaired German pointer polyuria was associated with slight hypokalemia, hypophosphatemia and alkalosis, as well as elevated plasma concentrations of a glucocorticoid-inducible iso-enzyme of alkaline phosphatase. Repeated measurements of urinary corticoids and normal suppressibility of the hypothalamus-pituitary-adrenocorticial axis excluded glucocorticoid excess. Urine osmolality (Uosm) did not increase during administration of the vasopressin analogue desmopressin. At the time water deprivation had caused Uosm to rise from 300 to 788 mOsm/kg, there was also plasma hypertonicity. During hypertonic saline infusion the osmotic threshold for vasopressin release was increased. The combination of elevated plasma aldosterone concentrations and unmeasurably low plasma renin activity pointed to primary hyperaldosteronism. As initially computed tomography (CT) did not reveal an adrenocortical lesion, the dog was treated with the aldosterone antagonist spironolactone. This caused Uosm to rise in a dose-dependent manner. However, well-concentrated urine was only achieved with doses that gave rise to adverse effects. Once repeated CT, using 2-mm-thick slices, had revealed a small nodule in the cranial pole of the left adrenal, unilateral adrenalectomy was performed which resolved the polyuria completely. Also the plasma concentrations of kalium, aldosterone and renin activity returned to within their respective reference ranges. The adrenocortical nodule had the histological characteristics of an aldosteronoma, with the non-affected zona glomerulosa being atrophic. In this dog with primary hyperaldosteronism the polyuria was characterized by vasopressin resistance and increased osmotic threshold of vasopressin release, similar to the polyuria of glucocorticoid excess. The possibility is discussed that the polyuria of glucocorticoid excess is actually a mineralocorticoid effect.

The aim of the present study was to study the pharmacokinetics, the antidiuretic effects and the safety of [D-Phe2, Thi3, alpha-Me-Abu4, Hyp7, D-Arg8]dC1-vasopressin, a new antidiuretic peptide (F992, Ferring, Sweden), administered as intravenous infusion to orally overhydrated male volunteers.Eight healthy male volunteers participated in this open study consisting of two parts: a dose titration study and a safety study. In the dose titration study ascending doses of F992 were administered to volunteers in pairs in order to find a dose that within 1 h after the infusion, in both subjects, caused a reduction of the urine flow rate to below 5 ml x min(-1) (target dose). Subsequently, this target dose was administered to all volunteers. In the safety study the target dose was doubled and given to all volunteers. On each study occasion, in both study parts, the subjects were orally overhydrated with water. F992 was administered as i.v. infusion approximately 1.5 h after the start of the hydration procedure. Throughout the study days, blood was sampled for determination of plasma concentrations of F992 and for safety evaluation. Urine was collected at intervals in order to estimate flow rate and osmolality.The target dose was found to be 4.0 microg as this dose fulfilled the criteria regarding antidiuretic effect, consequently 8.0 microg was administered to all subjects in the safety study. After infusion of 4.0 and 8.0 microg, the median half-lives of elimination were 4.72 (range 3.99-6.53) h and 3.85 (range 3.04-11.08) h, respectively. The plasma clearance and the volume of distribution at steady state were estimated to be 0.88 (SD 0.24) ml x min(-1) x kg(-1) and 326 (SD 68) ml x kg(-1)] after infusion of 4 microg. After the highest dose (8 microg), the corresponding estimates were 0.86 (SD 0.32) ml x min(-1) x kg(-1) and 299 (SD 81) ml x kg(-1), respectively. Significantly (P = 0.033) different maximum mean urine osmolalities were produced after infusion of 4.0 and 8.0 microg of F992 (534 (SD 318) vs 732 (SD 189) mOsmol x kg(-1)). The median times to reach these values showed some tendency to be longer for the highest dose, however statistical significance was not reached. No serious adverse events were observed during the study.We found it safe to administer F992 as infusion to overhydrated male volunteers. The results suggest that F992 has a longer half-life and a lower potency than the widely used peptide desmopressin.

AIMS—To examine the relation between nocturnal vasopressin release and response to treatment with the vasopressin analogue 1-desamino-8-D-arginine vasopressin (DDAVP) in children with primary monosymptomatic nocturnal enuresis. DESIGN—Children were recruited from a specific enuresis clinic and entered into a defined treatment programme. Nocturnal vasopressin concentrations were measured every 15 minutes over a four hour period during overnight admission. RESULTS—Sixty seven children were eligible for entry into the study, 35 of whom agreed to overnight sampling. There was a quadratic relation between mean plasma AVP and response to treatment with DDAVP, with very high or very low concentrations being unresponsive. Plasma AVP profiles ranged from low concentrations with little variability to high concentrations with wide variability. CONCLUSION—The ability to respond to DDAVP is related to endogenous AVP production and is influenced by neuronal patterning in early infancy. The best predictors of success with treatment were a past history of breast feeding, mean nocturnal AVP concentration, and the height of the child. The response was adversely affected by poor weight at birth and poor linear growth. The study suggests differing causes of nocturnal enuresis related to different patterns of AVP release.

Desmopressin [1-(mercaptopropanoic acid)-8-D-arginine vasopressin; dDAVP] is a vasopressin analogue with a selective antidiuretic effect. The oral bioavailability of desmopressin is limited due both to its high hydrophilicity leading to a low intestinal permeability and to low enzymatic stability. The degradation of desmopressin was investigated in aqueous buffer solutions (pH 6.00-9.00) containing the enzyme alpha-chymotrypsin at a concentration of 0.50 mg/ml at 37 degrees C. The degradation of desmopressin was also studied in solutions containing alpha-chymotrypsin in the concentration range 0.10-1.00 mg/ml (pH 7.40 and 37 degrees C). The rate of degradation was shown to be highly dependent on both enzyme concentration and pH. Maximal alpha-chymotrypsin activity was observed in the pH range 7.40-8.00. It was observed that phenylalanine was formed during the degradation of desmopressin. Phenylalanine was formed in the amount of 20% in 120 min. In the same time period 95% of desmopressin was degraded. The formation of phenylalanine can be explained from the substrate specificity of alpha-chymotrypsin. Cyclodextrins are known to stabilize drugs including peptides against both chemical and enzymatic degradation. In this study it was shown that hydroxypropyl cyclodextrins (alpha, beta and gamma) stabilized desmopressin against alpha-chymotrypsin-catalyzed degradation. The stabilization was by a factor of 3, 9 and 8 at the concentration 12.5% (w/v) for hydroxypropyl-alpha-cyclodextrin, hydroxylpropyl-beta-cyclodextrin and hydroxypropyl-gamma-cyclodextrin.

BoldiIarova K., ·. Faix, a. Leng: The Renal Response of Sheep Fed a High Protein Diet to Treatment with Vasopressin Analogue. Acta Vet. Brno 1999, 68: 99-104. This experiment was designed to test whether the long-term formation of highly concentrated urine rises the glomerular filtration rate in sheep like in simple stomach animals. Experiments were carried out on young sheep fed a high protein diet for 3 weeks. In order to produce animals with highly concentrating kidneys, the experimental group was treated with 1-desamino-8-D-arginine vasopressin (dDAVP, Adiuretin-SD, Ferring, Prague). Subcutaneous injections of 12.5 µg dDAVP given twice daily started one week before the measurements of renal function. The clearance protocol showed a decreased urine flow rate (from 3.19 ± 0.50 to 0.33 ± 0.03 ml.min-1, P < 0.001) without changes in glomerular filtration rate (80.18 ± 6.36 vs. 77.86 ± 6.26 ml.min -1 , NS) due to dDAVP. The plasma level of urea was significantly increased (from 5.76 ± 0.39 to 7.28 ± 0.25 mmol.l-1, P < 0.01) concomitantly with the larger renal urea reabsorption (from 239.72 ± 26.16 to 390.53 ± 33.25 µmol.min -1 , P < 0.01) in dDAVP treated group. Both fractional urea excretion (48.44 ± 3.12 vs. 30.33 ± 1.94 %, P < 0.001) and the amount of urea excreted were significantly reduced (206.22 ± 9.04 vs. 170.41 ± 10.76 µmol.min -1 , P < 0.05). One week-lasting treatment with a vasopressin analogue resulted in the decreased urea clearance (from 36.95 ± 2.07 to 23.76 ± 1.97 ml.min -1 , P < 0.001) but it did not influence the osmotic clearance (1.77 ± 0.10 vs. 1.62 ± 0.08 ml.min -1 , NS). In conclusion, the kidneys of sheep do not respond to a long-term formation of highly concentrated urine per se with a rise in the glomerular filtration rate. A possible explanation is that urea recycling through digestive tract of ruminants is of an order of magnitude larger than that in simple stomach animals. Sheep, kidney, GFR, urinary concentrating ability

In von Willebrand disease, the main goals of treatment are to correct the dual defect of haemostasis caused by a reduced or abnormal von Willebrand factor (vWF), i.e. the prolonged bleeding time (BT) and the deficiency of factor VIII coagulant activity (FVIII:C). The synthetic vasopressin analogue, desmopressin (DDAVP), has reduced the need for transfusions in most of the mild forms of von Willebrand disease but DDAVP is ineffective in type 3 and in other severe cases of types 1 and 2 von Willebrand disease. For many years cryoprecipitate has been the mainstay of replacement therapy but, after the introduction of virucidal methods, concentrates containing FVIII/vWF have been considered much safer than cryoprecipitate and proposed in von Willebrand disease management. FVIII/vWF concentrates have been produced and tested by many authors but there is only one report describing four virus-inactivated FVIII/vWF concentrates evaluated in a cross-over randomized trial. According to these in vitro and pharmacokinetic data, the following information can be derived: (a) no FVIII/vWF concentrate had an intact multimeric structure similar to that of normal plasma or of cryoprecipitate; (b) all FVIII/vWF concentrates were equally effective in attaining normal and sustained levels of FVIII:C postinfusion, although peak levels were more delayed in the concentrate devoid of FVIII:C; (c) no FVIII/vWF concentrate consistently normalized the BT in a sustained fashion. On the other hand, clinical haemostasis can be achieved in the management of bleeding episodes and of surgery for most of von Willebrand disease cases regardless of whether the BT is corrected; in the few rare cases with mucosal bleeding not controlled by FVIII/vWF concentrates, infusion of DDAVP or platelet concentrates can be administered in addition.

Previous work has shown that the arginine vasopressin fragment AVP 4–9 enhanced overall performance in the radial arm maze. This enhancement effect was due to improved working memory as well as to improved reference memory. The present study uses a behavioral approach to investigate whether these effects of vasopressin on memory are mediated by the hippocampus. Animals received either NMDA lesions to the hippocampus or sham operations and were then treated with AVP 4–9 or saline. The testing was performed in an eight-arm radial maze for 60 sessions, and all injections were given s.c. 30 min prior to testing. The hippocampal lesioned animals showed a marked deficit in working memory that was not ameliorated by AVP 4–9 ; however, the improvement in reference memory produced by the compound was as large as in healthy animals. Since the AVP treatment did not differentiate between the two hippocampal groups, the memory enhancing effects of AVP 4–9 were blocked by hippocampal lesions. It is concluded that vasopressin has a more general effect on memory and that its site of action includes but is not limited to the hippocampus.

We studied the effect of vasopressin analogue desglycinamide-arginine-vasopressin on changes in platelet hemostasis produced by intragastric administration of Ticlid or clopidogrel (inhibitors of ADP-induced platelet aggregation). Intranasal administration of the peptide under conditions of hemorrhagic diathesis produced a hemostatic effect and normalized some parameters of blood coagulation.