Serum Vasopressin Concentrations Research Articles

ARGININE VASOPRESSIN PROMOTES REDISTRIBUTION OF ADHESION JUNCTION PROTEIN E-CADHERIN IN KIDNEY EPITHELIAL CELLS

Acute and chronic kidney disease are two of the most commonly diagnosed kidney dysfuctions in both human and companion animals. The characteristics of an injured kidney include an increase of blood urea nitrogen, serum creatinine and a decrease of glomerular filtration rate. At the cellular level, infiltration of inflammatory cells, disruption of kidney epithelial cell lining and increased amount of type IV collagen have all been reported. Retrospective studies from human patients revealed a positve correlation between higher level of serum vasopressin and disease progression; however, the actual mechanism underlying vasopressin effect on kidney disease progression remains to be elucidated. In this study, we demonstrated that arginine vasopressin not only stimulates the de-polymerization of F-actin, but also promotes redistribution of adhesion junction protein E-Cadherin which is likely to be respoinsible for the lost of regular epithelial cell polarity in kidney tubules. Our data supported the detrimental effects of vasopressin on kidney epithelial cells and provided evidences on the potential cause and consequence relationship between patients with higer serum vasopressin concentration with the accelerated kidney tubule disruption.

Validation of an integrative mathematical model of dehydration and rehydration in virtual humans.

Water homeostasis is one of the body's most critical tasks. Physical challenges to the body, including exercise and surgery, almost always coordinate with some change in water handling reflecting the changing needs of the body. Vasopressin is the most important hormone that contributes to short‐term water homeostasis. By manipulating vascular tone and regulating water reabsorption in the collecting duct of the kidneys, vasopressin can mediate the retention or loss of fluids quickly. In this study, we validated HumMod, an integrative mathematical model of human physiology, against six different challenges to water homeostasis with special attention to the secretion of vasopressin and maintenance of electrolyte balance. The studies chosen were performed in normal men and women, and represent a broad spectrum of perturbations. HumMod successfully replicated the experimental results, remaining within 1 standard deviation of the experimental means in 138 of 161 measurements. Only three measurements lay outside of the second standard deviation. Observations were made on serum osmolarity, serum vasopressin concentration, serum sodium concentration, urine osmolarity, serum protein concentration, hematocrit, and cumulative water intake following dehydration. This validation suggests that HumMod can be used to understand water homeostasis under a variety of conditions.

Resuscitation Using Liposomal Vasopressin in an Animal Model of Uncontrolled Hemorrhagic Shock.

BackgroundCurrent research suggests that administration of vasopressin to patients with uncontrolled hemorrhagic shock (UHS) can avoid the detrimental effects associated with aggressive fluid resuscitation. However, vasopressin has a short half-life of 10~35 minutes in in vivo use and precludes its use in the pre-hospital setting. To increase the half-life of vasopressin, we proposed to synthesize liposome-encapsulated vasopressin and test it in a rat model of UHS.MethodsThe film hydration method was used to prepare liposomal vasopressin consisting of: Dipalmitoylphosphatidylcholine, cholesterol, and dipalmitoyl phosphatidylethanolamine (20:20:1 mole ratio). 42 rats were subjected to UHS and randomly received 5 different treatments (vasopressin, liposomal vasopressin, lactate ringer (LR), liposome only and sham). Outcome of UHS were measured using 4 common prognostic tests: mean arterial pressure (MAP), serum lactate level, inflammatory profile and pulmonary edema.ResultsThe dynamic light scattering results confirmed that we had prepared a successful liposomal vasopressin complex. Comparing the serum vasopressin concentration of liposomal vasopressin and vasopressin treated animals by ELISA, we found that the concentration of vasopressin for the liposomal vasopressin treated group is higher at 60 minutes. However, there was no significant difference between the MAP profile of rats treated with vasopressin and liposomal vasopressin in UHS. We also observed that animals treated with liposomal vasopressin performed indifferently to vasopressin treated rats in serum lactate level, inflammatory profile and edema profile. For most of our assays, the liposome only control behaves similarly to LR resuscitation in UHS rats.ConclusionWe have synthesized a liposomal vasopressin complex that can prolong the serum concentration of vasopressin in a rat model of UHS. Although UHS rats treated with either liposomal vasopressin or vasopressin showed no statistical differences, it would be worthwhile to repeat the experiments with different liposomal compositions.

The incidence of vasoplegia in adult patients with right-sided congenital heart defects undergoing cardiac surgery and the correlation with serum vasopressin concentrations

In adults with right-sided congenital heart disease, vasoplegia during and after cardiopulmonary bypass appears to be a frequent complication. The incidence of vasoplegia in the general adult and pediatric cardiac surgical population has been investigated, but the incidence in adult patients with right-sided congenital heart disease is unknown. Perioperative vasopressin levels during cardiac surgery have been studied in other cardiac surgical patients, but are not known in adults with right-sided congenital heart disease. The purpose of this study was to investigate the incidence of vasoplegia in adult patients undergoing right-sided cardiac surgical procedures requiring cardiopulmonary bypass and to determine the vasopressin response to cardiac surgery in this population. Twenty patients were enrolled and demographic, hemodynamic, cardiopulmonary bypass, and use of vasoactive medication data were collected. In addition, perioperative serum vasopressin levels were measured. Sixty adult patients undergoing left-sided cardiac surgery served as controls. The incidence of vasoplegia in the control patients was 10% and the incidence in the adult patients with right-sided congenital heart disease was 20%. Vasopressin levels were low at baseline (0.5 ± 0.5 pg/mL), increased slightly after induction of anesthesia (0.6 ± 0.6 pg/mL), increased after initiation of cardiopulmonary bypass (99.7 ± 168.2 pg/mL), and decreased after surgery (31.3 ± 43.6 pg/mL). This study showed that the incidence of vasoplegia (20%) in patients with right-sided congenital heart disease undergoing cardiac surgery was double that of a population of patients undergoing aortic valve surgery (10%). Serum vasopressin concentration was not associated with vasoplegia in this population of congenital cardiac surgical patients.

Vasopressin in definite Meniere's disease with positive electrocochleographic findings

Conclusion: There was no evidence of a mean raised vasopressin level in 80 subjects suffering from definite Meniere's disease with positive electrocochleographic findings. There was no correlation with stress. The only group with a mildly raised level comprised those who had had a vertigo attack within a day. The most likely cause is nausea, which is the most potent trigger for vasopressin release. Objective: It has been claimed that patients with Meniere's disease have raised vasopressin levels. This has been linked with a long-standing notion that that there is a link between stress and Meniere's disease, so that an increase in vasopressin could trigger a vertigo attack. Methods: Serum vasopressin concentrations were measured in 80 patients with Meniere's disease whose diagnosis was based on conventional symptom criteria plus electrocochleographic evidence of endolymphatic hydrops. Results: The community mean for vasopressin is 2.2 pmol/L (SD = 2.4). For all 80 Meniere's patients the mean vasopressin concentration was 2.1 pmol/L (SD = 1.6), and 2.8 pmol/L (SD = 0.9) when the last attack was within a day.

Impact of Low‐dose Vasopressin on Trauma Outcome: Prospective Randomized Study

We previously found that regardless of the animal injury model used resuscitation strategies that minimize fluid administration requirements lead to better outcomes. We hypothesized that a resuscitation regimen that limited the total volume of fluid administered would reduce morbidity and mortality rates in critically ill trauma patients. We performed a double-blind randomized trial to assess the safety and efficacy of adding vasopressin to resuscitative fluid. Subjects were hypotensive adults who had sustained acute traumatic injury. Subjects were given fluid alone (control group) or fluid plus vasopressin (experimental group), first as a bolus (4 IU) and then as an intravenous infusion of 200 ml/h (vasopressin 2.4 IU/h) for 5 h. We randomly assigned 78 patients to the experimental group (n=38) or the control group (n=40). The groups were similar in age, sex, preexisting medical illnesses, and mechanism and severity of injury. Serum vasopressin concentrations were higher in the experimental group than in the control group at admission, after infusion of vasopressin (p=0.01), and 12 h later. The experimental group required a significantly lower total volume of resuscitation fluid over 5 days than did the control group (p=0.04). The mortality rate at 5 days was 13% in the experimental group and 25% in the control group (p=0.19). The rates of adverse events, organ dysfunction, and 30-day mortality were similar. This is the first trial to investigate the impact of vasopressin administration in trauma patients. Infusion of low-dose vasopressin maintained elevated serum vasopressin levels and decreased fluid requirements after injury.

Serum Vasopressin Concentrations During Orthotopic Liver Transplantation

Background We report measurements of the temporal response of serum vasopressin concentrations in the period after reperfusion of the liver graft during orthotopic liver transplantation (OLT). Methods Vasopressin concentrations were determined in 11 adult patients undergoing OLT by radioimmunoassay of samples collected after induction, at 5 minutes prior to reperfusion, and at 10, 20, 30, 40, 50, 60, 90, and 120 minutes after reperfusion. Results Pre-incision vasopressin concentrations ranged from <0.5 to 2.6 pg/mL (reference serum vasopressin, <1.7 pg/mL). Overall, levels increased before reperfusion, but fell thereafter. Individual patients manifested elevated levels during the period after reperfusion. Values immediately before reperfusion exhibited most variability, ranging from 0.8 to 40 pg/mL (median, 15; interquartile range [IQR], 4–29) Median vasopressin concentrations 10 minutes postreperfusion were 7.6 pg/mL (IQR, 3–27). Only 3 of the 11 patients failed to generate vasopressin levels >20 pg/mL. In each of these patients, hemodynamics were satisfactory without the need for additional pressor infusion. Maximum vasopressin concentration measured in any patient was 85 pg/mL. There was no correlation between vasopressin concentration and mean blood pressure or systemic vascular resistance index. Conclusion Vasopressin concentrations during OLT vary widely and are elevated periodically during the anhepatic and postreperfusion stages, with no apparent relationship between vasopressin concentrations and blood pressure. Although vasopressin concentrations were not as high as those measured during some other clinical situations, these data suggest that a relative vasopressin deficiency is not a direct cause of hypotension during OLT.

Acute Changes in Systemic Hemodynamics and Serum Vasopressin After Complete Cervical Spinal Cord Injury in Piglets

Spinal cord injury (SCI) produces acute hemodynamic alterations through disruption of sympathetic output of the autonomic nervous system and places individuals with SCI at high risk of secondary ischemic insult to the spinal cord as well as to other organs. The purpose of this study was to examine hemodynamics and serum vasopressin concentration in the acute period following complete cervical SCI in piglets. We developed a new model of traumatic complete cervical SCI in piglets and measured acute hemodynamic variables and serum arginine vasopressin (AVP) concentrations at baseline and for 4 h after SCI under fentanyl anesthesia. Complete cervical SCI caused an immediate tachycardia which lasted for approximately 1 h, immediate hypotension which was sustained for the 4-h duration of the study, decreases in both systemic and pulmonary vascular resistance, and a compensatory increase in cardiac output, which resulted initially from an increase in heart rate (HR) but was later sustained after resolution of tachycardia by an increase in cardiac stroke volume. Serum AVP concentration increased significantly after SCI and did not change in the control group. Neurogenic shock did not occur due to the robust increase in cardiac output and cardiac stroke volume. Complete cervical SCI produces hemodynamic alterations consistent with the withdrawal of sympathetic tone. Although mean arterial pressure (MAP) decreased significantly after SCI, the increase in serum vasopressin may have played a role in maintaining blood pressure and preventing circulatory collapse, a complication which is encountered frequently in patients with cervical and upper thoracic SCI.

Serum vasopressin concentrations in critically ill patients in the intensive care unit

The aim of the study is the measurement of serum vasopressin concentrations in the mixed critically ill patients, 24 hours after admission to the ICU and just before the discharge.

Copeptin, a stable peptide derived from the vasopressin precursor, is elevated in serum of sepsis patients

Vasopressin is one of the key regulators of the body's water and solute balance. When this balance is pathologically disturbed, determination of serum vasopressin concentrations might be a helpful tool for guiding therapy. However, due to its instability and considerable association to platelets, reliable measurement of circulating vasopressin is difficult to achieve, if at all. In search of a more robust way for quantifying vasopressin release, we identified copeptin, a glycopeptide with unknown function, as an alternative diagnostic target. Since copeptin is derived from the same precursor peptide as vasopressin, released amounts of copeptin should mirror those of vasopressin. With a newly developed sensitive sandwich immunoassay, we detected strongly elevated concentrations of fully processed copeptin in serum of septic shock patients. The magnitude of elevation and the high stability of copeptin in serum and plasma indicate that copeptin measurement is not affected by the problems, which are associated with the direct measurement of vasopressin, and thus is apparently suitable to indirectly determine the release of vasopressin.

Physiological and Biochemical Indices of Neurohypophyseal Function in the Aging Fischer Rat

In order to resolve conflicting reports in the literature on the effect of aging on the hypothalamo neurohypophyseal system (HNS) in rats, multiple parameters associated with the HNS were evaluated in young (4 months), fully mature (14 months), and old (25 months) Fischer 344 rats under basal and stimulated conditions. The hypothalamic hormones oxytocin and vasopressin were compared in radioimmunoassay of serum, urine, brain and pituitary. Information on body weight, water intake, urine output, serum hematocrit and plasma osmolality was also obtained from the same subjects and analyzed together with these data. Finally, semi quantitative histofluorescence assessment of the noradrenergic innervation of the mediobasal hypothalamus from the same animals was performed to determine the extent of central afferent input to the HNS with advancing age. The circulating levels of vasopressin and oxytocin did not significantly differ in the three age groups under basal conditions. Serum vasopressin concentration was increased following water deprivation, and the increase was comparable in all age groups. Serum oxytocin was also increased following water deprivation in all groups, but the increase was greater in the 25-month-old rats relative to the 4-month-old rats. Urinary excretion of vasopressin was used as an index of daily vasopressin secretion. The urinary concentration of vasopressin was less in aged rats relative to young controls, though an increased urine volume in the mature and old animals meant that total vasopressin excretion in the urine was comparable at all ages studied. The increased urine volume in the mature and aged rats does not appear to reflect a decrease in renal sensitivity to vasopressin, since all age groups demonstrated a comparable reduction in urine volume during water deprivation, at comparable concentrations of circulating vasopressin. These data suggest that the increase in urine volume observed in the 14- and 25-month-old rats may be a function of increased fluid intake rather than hyperactivity in the HNS. The concentrations of both peptides were reduced in the posterior pituitary of aged rats, though again, the total amount of peptide in the gland did not change. Only oxytocin showed an age-related change in the hypothalamus, decreasing in the oldest subjects. These data indicate that the ability to secrete adequate quantities of vasopressin in response to dehydration is not compromised in Fisher 344 rats up to 25 months of age.

Arginine vasopressin secretion in thyroidectomized sheep..

Indwelling, exteriorized, jugular vein catheters were placed in five thyroidectomized ewes at a time when myxedema was manifested clinically and chemically and three euthyroid sheep were used as controls. Post-operatively, tracer doses of [125I]-iodovasopressin were injected and serial blood specimens were obtained for determination of volume of distribution, plasma disappearance, and blood production rates. Serum vasopressin was measured by radioimmunoassay. The mean volumes of distribution for vasopressin in the hypothyroid and euthyroid sheep, respectively, were 8.15 and 5.90 liters, mean t1/2 of vasopressin 9.5 and 19.3 min, mean serum vasopressin concentrations 5.1 and 1.2 muU/ml, and mean blood production rates 2.84 and 0.23 mU/kg/h. Renal and organ biologic effectiveness of the elevated vasopressin levels was suggested by the lowered serum osmolalities in the hypothyroid sheep over controls (272 vs. 301 mosmol/kg). These results suggest an augmented secretion of vasopressin in the myxedematous state.