Terlipressin, a provasopressin drug exhibits direct vasoconstrictor properties: consequences on heart perfusion and performance

Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications

Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.

Continuous vs. intermittent terlipressin infusion for portal hypertension: a systematic review and meta-analysis

Background

Portal hypertension, a major complication of chronic liver disease, often leads to life-threatening variceal bleeding, managed effectively with vasoactive drugs like terlipressin. However, the most optimal method of terlipressin administration, continuous versus intermittent infusion, remains a subject of debate, necessitating this systematic review and meta-analysis for evidence-based decision-making in managing this critical condition.

Methods

This systematic review and meta-analysis adhered to the PRISMA standards and explored multiple databases until 6 April 2023, such as MEDLINE through PubMed, Scopus, Web of Science, and CENTRAL. Independent reviewers selected randomized controlled trials (RCTs) that met specific inclusion criteria. After assessing study quality and extracting necessary data, statistical analysis was performed using Review Manager (RevMan), with results presented as risk ratios (RR) or mean differences.

Results

Five RCTs (n=395 patients) were included. The continuous terlipressin group had a significantly lower risk of rebleeding (RR=0.43, P=0.0004) and treatment failure (RR=0.22, P=0.02) and fewer total adverse effects (RR=0.52, P<0.00001) compared to the intermittent group. However, there were no significant differences between the two groups in mean arterial pressure (P=0.26), length of hospital stays (P=0.78), and mortality rates (P=0.65).

Conclusion

This study provides robust evidence suggesting that continuous terlipressin infusion may be superior to intermittent infusions in reducing the risk of rebleeding, treatment failure, and adverse effects in patients with portal hypertension. However, further large-scale, high-quality RCTs are required to confirm these findings and to investigate the potential benefits of continuous terlipressin infusion on mortality and hospital stays.

Respiratory events with terlipressin and albumin in hepatorenal syndrome: A review and clinical guidance

Hepatorenal syndrome-acute kidney injury (HRS-AKI) is a serious complication of severe liver disease with a clinically poor prognosis. Supportive care using vasoconstrictors and intravenous albumin are the current mainstays of therapy. Terlipressin is an efficacious vasoconstrictor that has been used for 2 decades as the first-line treatment for HRS-AKI in Europe and has demonstrated greater efficacy in improving renal function compared to placebo and other vasoconstrictors. One of the challenges associated with terlipressin use is monitoring and mitigating serious adverse events, specifically adverse respiratory events, which were noted in a subset of patients in the recently published CONFIRM trial, the largest randomized trial examining terlipressin use for HRS-AKI. In this article, we review terlipressin's pharmacology, hypothesize how its mechanism contributes to the risk of respiratory compromise and propose strategies that will decrease the frequency of these events by rationally selecting patients at lower risk for these events.

A Romanian study on the impact of glypressin in laparoscopic myomectomy

A major myomectomy-associated problem is excessive blood loss. The aim of the present study was to evaluate the effect of glypressin on blood loss during laparoscopic myomectomy (LM) in women with uterine myomas. A total of 188 women scheduled for LM for uterine myomas were divided into two groups. The one group of women (n=64) received a 5-ml intramyometrial injection of glypressin 0.2 mg/ml (glypressin group; group 1). The other group of women (n=124) (group 2) had an LM performed without any other method to reduce blood loss. The decrease in postoperative hemoglobin (Hb), hematocrit (Ht), morbidity and duration of hospital stay were assessed. The results revealed that Hb and Ht (as it was presumed) exhibited similar changes in our study. Statistically significant differences (P<0.05) were obtained between the two groups in terms of Hb and Ht; after LM both Hb and Ht were decreased. In conclusion, the impact of glypressin administration in hemorrhage control in uterine leiomyomas may establish new future perspectives, regarding its administration in gynecological hemorrhagic pathologies.

Vasopressin Loading for Refractory Septic Shock: A Preliminary Analysis of a Case Series

Background: Vasopressin is one of the strong vasopressor agents associated with ischemic events. Responses to the administration of vasopressin differ among patients with septic shock. Although the administration of a high dose of vasopressin needs to be avoided, the effects of bolus loading have not yet been examined. Since the half-life of vasopressin is longer than that of catecholamines, we hypothesized that vasopressin loading may be effective for predicting responses to its continuous administration. Methods: We retrospectively analyzed consecutive cases of septic shock for which vasopressin was introduced with loading under noradrenaline at >0.2 μg/kg/min during the study period. Vasopressin was administered in a 1 U bolus followed by its continuous administration at 1 U/h. The proportion of patients with a negative catecholamine index (CAI) change 6 h after the introduction of vasopressin was set as the primary outcome. We defined non-responders for exploration as those with a mean arterial pressure change <18 mmHg 1 min after vasopressin loading, among whom none had a change in CAI <0. Results: Twenty-one consecutive cases were examined in the present study, and included 14 responders and 7 non-responders. The primary outcome accounted for 71.4% of responders and 0% of non-responders, with a significant difference (p = 0.0039). Median CAI changes 2, 4, and 6 h after the administration of vasopressin were 0, -5, and -10 in responders and +20, +10, and +10 in non-responders, respectively. CAI was not reduced in any non-responder. Outcomes including mortality were not significantly different between responders and non-responders. Digital ischemia (1/21) and mesenteric ischemia (1/21) were observed. Conclusions: Vasopressin loading may predict responses to its continuous administration in septic shock patients. Further investigations involving a safety analysis are needed.

Use of terlipressin in critically ill children with liver disease

Background

Terlipressin, a long-acting synthetic analogue of vasopressin has been used in the adult population for various indications including hepatorenal syndrome (HRS-AKI), esophageal variceal hemorrhage (EVH) and shock, but its use in pediatrics is still limited to individualized cases and data on safety and efficacy is scant.

Methods

We reviewed the patient records of children with liver disease and Acute Kidney Injury requiring terlipressin admitted to the Paediatric Intensive Care Unit (PICU) of King’s College Hospital, London from January 2010–December 2017, with special emphasis on its effect on renal parameters and adverse event profile.

Results

Twenty-one terlipressin administration records in a total of 16 patients (median) (IQR) 10 years (6.1–14.4) were included. The drug was initially given as a bolus dose in all cases, followed by either bolus or infusion with median dosage being 5.2 (3.8–6.7) mcg/kg/hour. After administration, a sustained increase of mean arterial pressure was observed. There was an improvement in serum creatinine (Cr) (at 24 h; p = 0.386) and increase in urine output (UO), especially in the hepatorenal syndrome subgroup (HRS-AKI). We found minimal evidence of gastrointestinal side effects including feeding intolerance and vasoconstrictive side effects including cyanosis / ischaemia of extremities.

Conclusion

Terlipressin was found to be safe in critically sick children with liver disease with positive impact on renal parameters which might be taken as a surrogate marker of HRS reversal, though effects on outcomes are difficult to ascertain. It is important to be aware of all its side-effects and actively watch for them. Future prospective studies are warranted to validate these findings.

Terlipressin for the treatment of septic shock in adults: a systematic review and meta-analysis

Background

Catecholamines are the first-line vasopressors used in patients with septic shock. However, the search for novel drug candidates is still of great importance due to the development of adrenergic hyposensitivity accompanied by a decrease in catecholamine activity. Terlipressin (TP) is a synthetic vasopressin analogue used in the management of patients with septic shock. In the current study, we aimed to compare the effects of TP and catecholamine infusion in treating septic shock patients.

Methods

A systematic review and meta-analysis was conducted by searching articles published in PUBMED, EMBASE, and the Cochrane Central Register of Controlled Trials between inception and July 2018. We only selected randomized controlled trials evaluating the use of TP and catecholamine in adult patients with septic shock. The primary outcome was overall mortality. The secondary outcomes were the ICU length of stay, haemodynamic changes, tissue perfusion, renal function, and adverse events.

Results

A total of 9 studies with 850 participants were included in the analysis. Overall, no significant difference in mortality was observed between the TP and catecholamine groups (risk ratio(RR), 0.85 (0.70 to 1.03); P = 0.09). In patients < 60 years old, the mortality rate was lower in the TP group than in the catecholamine group (RR, 0.66 (0.50 to 0.86); P = 0.002). There was no significant difference in the ICU length of stay (mean difference, MD), − 0.28 days; 95% confidence interval (CI), − 1.25 to 0.69; P = 0.58). Additionally, TP improved renal function. The creatinine level was decreased in patients who received TP therapy compared to catecholamine-treated participants (standard mean difference, SMD), − 0.65; 95% CI, − 1.09 to − 0.22; P = 0.003). No significant difference was found regarding the total adverse events (Odds Ratio(OR), 1.48(0.51 to 4.24); P = 0.47), whereas peripheral ischaemia was more common in the TP group (OR, 8.65(1.48 to 50.59); P = 0.02).

Conclusion

The use of TP was associated with reduced mortality in septic shock patients less than 60 years old. TP may also improve renal function and cause more peripheral ischaemia. PROSPERO registry: CRD42016035872.

In vitro binding and receptor-mediated activity of terlipressin at vasopressin receptors V1 and V2

Terlipressin, a synthetic, systemic vasoconstrictor with selective activity at vasopressin-1 (V₁) receptors, is a pro-drug for the endogenous/natural porcine hormone [Lys₈]-vasopressin (LVP). We investigated binding and receptor-mediated cellular activities of terlipressin, LVP, and endogenous human hormone [Arg₈]-vasopressin (AVP) at V₁ and vasopressin-2 (V₂) receptors. Cell membrane homogenates of Chinese hamster ovary cells expressing human V₁ and V₂ receptors were used in competitive binding assays to measure receptor-binding activity. These cells were used in functional assays to measure receptor-mediated cellular activity of terlipressin, LVP, and AVP. Binding was measured by [³H]AVP counts, and the activity was measured by fluorometric detection of intracellular calcium mobilization (V₁) and cyclic adenosine monophosphate (V₂). Binding potency at V₁ and V₂ was AVP>LVP>>terlipressin. LVP and terlipressin had approximately sixfold higher affinity for V₁ than for V₂. Cellular activity potency was also AVP>LVP>>terlipressin. Terlipressin was a partial agonist at V₁ and a full agonist at V₂; LVP was a full agonist at both V₁ and V₂. The in vivo response to terlipressin is likely due to the partial V₁ agonist activity of terlipressin and full V₁ agonist activity of its metabolite, LVP. These results provide supportive evidence for previous findings and further establish terlipressin pharmacology for vasopressin receptors.

Terlipressin, a vasoactive prodrug recommended in hepatorenal syndrome, is an agonist of human V1, V2 and V1B receptors: Implications for its safety profile

Terlipressin is recommended as a gold standard to treat hepatorenal syndrome complicating liver cirrhosis. It is presented as a specific V1A receptor agonist, beyond its enzymatic conversion into lysine⁸-Vasopressin (LVP), able to counteract the splanchnic vasodilation. However, the complete pharmacological characterization of this drug with respect to the different vasopressin receptor subtypes is missing. We studied terlipressin intrinsic properties, focusing not only on V1A, but also on other vasopressin receptor subtypes. The experimental studies were conducted on rat and human cellular models. Binding experiments were performed on rat liver membranes and CHO cells transfected with the different human vasopressin receptor subtypes. Agonist status was assessed from inositol phosphate or cyclic AMP assays, and measurement of intracellular calcium variations, performed on cultured vascular smooth muscle cells from rat aorta and human uterine artery and CHO cells. Terlipressin binds to the rat and human V1A receptors with an affinity in the micromolar range, a value 120 fold lower than that of LVP. It induces a rapid and transient intracellular calcium increase, a robust stimulation of phospholipase C but with reduced maximal efficiencies as compared to LVP, indicating a partial V1A agonist property. In addition, terlipressin is also a full agonist of human V2 and V1B receptors, with also a micromomolar affinity.

CONCLUSIONS

Terlipressin is a non-selective vasopressin analogue, exhibiting intrinsic agonist properties. Its full V2 receptor agonism may result in renal effects potentially aggravating water retention and hyponatremia of cirrhosis.

[Hepatorenal syndrome in decompensated cirrhosis : A special form of acute renal failure]

Renal failure is a serious complication in patients with advanced cirrhosis. It occurs in about 20 % of patients hospitalized with cirrhosis. In about 70 % it is caused by prerenal failure, and in 30 % it is due to intrarenal causes. In about 70 % of patients with rperenal failure, renal function can be restored with fluid replacement, but the remaining 30 % are unresponsive to volume expansion. Minor increase in serum creatinine have been shown to be clinically relevant and can adversely affect survival. Therefore early efforts should be made to avoid precipitation of renal failure.Hepatorenal syndrome (HRS) is a  fully reversible impairment of renal function in patients with cirrhosis unresponsive to volume expansion characterized by an acute progressive decrease in kidney function (serumcreatinin > 1,5 mg/dl) - type 1 HRS, whereas type 2 HRS features a decrease in kidney function over a long time, mostly in patients with refractory ascites. Therapy with vasoconstrictors like terlipressin to reverse splanchnic vasodilation, together with albumin is effective in 30-50 % of patients with HRS 1 and improves survival. The only effective longterm therapy is livertransplantation. An improvement of kidney fuction before transplantation is associated with a better outcome and posttransplant kidney function.

Pregnancy and liver disease

Pregnancy associated liver diseases affect up to 3% of pregnant women and are the most frequent cause of liver dysfunction in pregnancy. When severe, they are associated with significant morbidity and mortality for both mother and infant. A rapid evaluation to distinguish them from non-pregnancy related liver dysfunction is essential, in order to facilitate appropriate management. Liver disease unrelated to pregnancy can present de novo in pregnancy, or pregnancy can occur in women with preexisting liver pathology (Table 1). Research and subsequent advances in medical care have resulted in improved but still not satisfactory maternal and fetal outcomes. In this review we provide an overview of the liver diseases specific to the pregnant state and an update on their pathogenesis, treatment and outcomes. The risks of pregnancy in women with pre-existent liver pathology is detailed and recent advances in our understanding of specific risks and outcomes are discussed.

A Selective V(1A) Receptor Agonist, Selepressin, Is Superior to Arginine Vasopressin and to Norepinephrine in Ovine Septic Shock

OBJECTIVE

Selective vasopressin V(1A) receptor agonists may have advantages over arginine vasopressin in the treatment of septic shock. We compared the effects of selepressin, a selective V(1A) receptor agonist, arginine vasopressin, and norepinephrine on hemodynamics, organ function, and survival in an ovine septic shock model.

DESIGN

Randomized animal study.

SETTING

University hospital animal research laboratory.

SUBJECTS

Forty-six adult female sheep.

INTERVENTIONS

Fecal peritonitis was induced in the anesthetized, mechanically ventilated, fluid-resuscitated sheep, and they were randomized in two successive phases. Three late-intervention groups (each n = 6) received IV selepressin (1 pmol/kg/min), arginine vasopressin (0.25 pmol [0.1 mU]/kg/min), or norepinephrine (3 nmol [0.5 μg]/kg/min) when mean arterial pressure remained less than 70 mm Hg despite fluid challenge; study drugs were thereafter titrated to keep mean arterial pressure at 70-80 mm Hg. Three early-intervention groups (each n = 7) received selepressin, arginine vasopressin, or norepinephrine at the same initial infusion rates as for the late intervention, but already when mean arterial pressure had decreased by 10% from baseline; doses were then titrated as for the late intervention. A control group (n = 7) received saline. All animals were observed until death or for a maximum of 30 hours.

MEASUREMENTS AND MAIN RESULTS

In addition to hemodynamic and organ function assessment, plasma interleukin-6 and nitrite/nitrate levels were measured. In the late-intervention groups, selepressin delayed the decrease in mean arterial pressure and was associated with lower lung wet/dry weight ratios than in the other two groups. In the early-intervention groups, selepressin maintained mean arterial pressure and cardiac index better than arginine vasopressin or norepinephrine, slowed the increase in blood lactate levels, and was associated with less lung edema, lower cumulative fluid balance, and lower interleukin-6 and nitrite/nitrate levels. Selepressin-treated animals survived longer than the other animals.

CONCLUSIONS

In this clinically relevant model, selepressin, a selective V(1A) receptor agonist, was superior to arginine vasopressin and to norepinephrine in the treatment of septic shock, especially when administered early.

Treatment and management of ascites and hepatorenal syndrome: an update

Ascites and renal dysfunction are frequent complications experienced by patients with cirrhosis of the liver. Ascites is the pathologic accumulation of fluid in the peritoneal cavity, and is one of the cardinal signs of portal hypertension. The diagnostic evaluation of ascites involves assessment of its granulocyte count and protein concentration to exclude complications such as infection or malignoma and to allow risk stratification for the development of spontaneous peritonitis. Although sodium restriction and diuretics remain the cornerstone of the management of ascites, many patients require additional therapy when they become refractory to this treatment. In this situation, the treatment of choice is repeated large-volume paracentesis. Alteration in splanchnic hemodynamics is one of the most important changes underlying the development of ascites. Further splanchnic dilation leads to changes in systemic hemodynamics, activating vasopressor agents and leading to decreased renal perfusion. Small alterations in renal function influence the prognosis, which depends on the cause of renal failure. Prerenal failure is evident in about 70% of patients, whereas in about 30% of patients the cause is hepatorenal syndrome (HRS), which is associated with a worse prognosis. Therefore, effective therapy is of great clinical importance. Recent data indicate that use of the new definition of acute kidney injury facilitates the identification and treatment of patients with renal insufficiency more rapidly than use of the current criteria for HRS. In this review article, we evaluate approaches to the management of patients with ascites and HRS.

β-adrenergic receptor-mediated cardiac contractility is inhibited via vasopressin type 1A-receptor-dependent signaling

BACKGROUND

Enhanced arginine vasopressin levels are associated with increased mortality during end-stage human heart failure, and cardiac arginine vasopressin type 1A receptor (V1AR) expression becomes increased. Additionally, mice with cardiac-restricted V1AR overexpression develop cardiomyopathy and decreased β-adrenergic receptor (βAR) responsiveness. This led us to hypothesize that V1AR signaling regulates βAR responsiveness and in doing so contributes to development of heart failure.

METHODS AND RESULTS

Transaortic constriction resulted in decreased cardiac function and βAR density and increased cardiac V1AR expression, effects reversed by a V1AR-selective antagonist. Molecularly, V1AR stimulation led to decreased βAR ligand affinity, as well as βAR-induced Ca(2+) mobilization and cAMP generation in isolated adult cardiomyocytes, effects recapitulated via ex vivo Langendorff analysis. V1AR-mediated regulation of βAR responsiveness was demonstrated to occur in a previously unrecognized Gq protein-independent/G protein receptor kinase-dependent manner.

CONCLUSIONS

This newly discovered relationship between cardiac V1AR and βAR may be informative for the treatment of patients with acute decompensated heart failure and elevated arginine vasopressin.

Pharmacological characterization of FE 201874, the first selective high affinity rat V1A vasopressin receptor agonist

BACKGROUND AND PURPOSE

Distinct vasopressin receptors are involved in different physiological and behavioural functions. Presently, no selective agonist is available to specifically elucidate the functional roles of the V1A receptor in the rat, one of the most widely used animal models. FE 201874 is a new derivative of the human selective V1A receptor agonist F180. In this study, we performed a multi-approach pharmacological and functional characterization of FE 201874 to determine whether it is selective for V1A receptors.

EXPERIMENTAL APPROACH

We modified an available human selective V1A receptor agonist (F180) and determined its pharmacological properties in cell lines expressing vasopressin/oxytocin receptors (affinity and coupling to second messenger cascades), in an ex vivo model (aorta ring contraction) and in vivo in rats (proliferation of adrenal cortex glomerulosa cells and lactation).

KEY RESULTS

FE 201874 exhibited nanomolar affinity for the rat V1A receptor; it was highly selective towards the rat V1B and V2 vasopressin receptors and behaved as a full V1A agonist in all the pharmacological tests performed. FE 201874 bound to the oxytocin receptor, but with moderate affinity, and behaved as an oxytocin antagonist in vitro, but not in vivo.

CONCLUSIONS AND IMPLICATIONS

On functional grounds, all the data demonstrate that FE 201874 is the first selective agonist of the rat V1A receptor isoform available. Hence, FE 201874 may have potential as a treatment for the vasodilator-induced hypotension occurring in conditions such as septic shock and could be the most suitable compound for discriminating between the behavioural effects of arginine vasopressin and oxytocin.

Involvement of the microvasculature in the pathogenesis of terlipressin-related myocardial infarction

We report an autopsy case of a 24-year-old man with diagnoses of advanced alcoholic liver cirrhosis, portal hypertension, and esophageal variceal bleeding that presented extensive myocardial infarction after treatment with terlipressin. On postmortem examination the cut surface of the heart presented myocardial infarction implicating the left ventricle free wall, apex of the heart and ventricular septum. Light microscopic examination revealed that the extensive area of cardiac infarction was the result of the sum of diffuse foci of microinfarction of various ages interspersed with small clusters of preserved myocytes. Moreover, the epicardial vessels were patent while the small intramyocardial vessels presented thickened wall, apparent reduction in lumen diameter and disruption of endothelial cells indicative of spasm. The observations in this case allow clear insight into the involvement of the microcirculation in the pathogenesis of myocardial infarction with the use of terlipressin.

Hemodynamic effects of continuous versus bolus infusion of terlipressin for portal hypertension: a randomized comparison

BACKGROUND AND AIM

The hemodynamics of patients with portal hypertension within 4 h after a single injection of terlipressin has been studied. However, the hemodynamics in a longer phase under different infusion styles is unknown. This study aims to compare the effects of bolus and continuous infusion of terlipressin on systemic and hepatic hemodynamics in patients with portal hypertension.

METHODS

Twenty patients who underwent transjugular intrahepatic portosystemic shunt procedure were randomly assigned to be treated with either intravenous bolus infusion of terlipressin (1 mg) followed by a continuous infusion (4 mg/24 h, n = 10), or intravenous bolus injection of terlipressin (2 mg) followed by intermittent injections (1 mg/6 h, n = 10). The mean arterial pressure, heart rate, and portal venous pressure (PVP) were monitored and recorded at baseline, 1 min, 5 min, 10 min, 30 min, and then once an hour. Serum renin activity, serum angiotensin II, and aldosterone levels were measured prior to and 24 h after the administration of terlipressin.

RESULTS

PVP dropped rapidly in both groups, and reduced 16.46% and 28.22%, respectively, at the 1-h time point. Thereafter, PVP remained stable in continuous group while rebounded obviously in intermittent group. One hour after the start of drug administration, heart rate decreased significantly in both groups (84.1 ± 12.8 vs 73.8 ± 12.6 in intermittent group and 86.7 ± 11.5 vs 77.1 ± 13.6 in continuous group, P < 0.005), and mean arterial pressure increased in both groups, although no statistical differences were found.

CONCLUSION

Continuous infusion of terlipressin reduces PVP stably and may become an alternative to traditional bolus injection.

Terlipressin decreases vascular endothelial growth factor expression and improves oxygenation in patients with acute respiratory distress syndrome and shock

BACKGROUND

Recent clinical data suggest that treatment with terlipressin (TP) may be more advantageous for septic shock than catecholamines. However, it is unknown whether TP would be effective for acute respiratory distress syndrome (ARDS) patients with shock.

OBJECTIVES

The aim of this study was to compare the impact of TP vs. dopamine on hemodynamic variables and vascular endothelial growth factor (VEGF) in ARDS patients with shock.

METHODS

We studied 32 ARDS patients with shock despite fluid loading, who were randomized to receive TP (16 patients) or dopamine (16 patients). TP was administered as a continuous intravenous dose of 1.3 μg/kg/h and dopamine was administered in doses up to 20 μg/kg/min to maintain a mean arterial pressure of 70 ± 5 mm Hg for 48 h. Hemodynamic changes, ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO(2)/FiO(2)), and VEGF were recorded prospectively.

RESULTS

There was a significant correlation between the plasma VEGF level and the lung injury score at baseline (r = 0.387, p < 0.01). VEGF concentrations significantly decreased from baseline levels in the TP group (p < 0.05) at 48 h; there was no difference in the dopamine group (p > 0.05) at 48 h vs. baseline. There was no significant difference in the tumor necrosis factor-α concentration between the groups.

CONCLUSIONS

TP treatment has the potential to inhibit VEGF and improve oxygenation in patients with shock in the early stage of ARDS.

Effects of terlipressin and naloxone compared with epinephrine in a rat model of asphyxia-induced cardiac arrest

OBJECTIVE

To evaluate the hemodynamic and metabolic effects of terlipressin and naloxone in cardiac arrest.

METHODS

Cardiac arrest in rats was induced by asphyxia and maintained for 3.5 minutes. Animals were then resuscitated and randomized into one of six groups: placebo (n = 7), epinephrine (0.02 mg/kg; n = 7), naloxone (1 mg/kg; n = 7) or terlipressin, of which three different doses were tested: 50 µg/kg (TP50; n = 7), 100 µg/kg (TP100; n = 7) and 150 µg/kg (TP150; n = 7). Hemodynamic variables were measured at baseline and at 10 (T10), 20 (T20), 30 (T30), 45 (T45) and 60 (T60) minutes after cardiac arrest. Arterial blood samples were collected at T10, T30 and T60.

RESULTS

The mean arterial pressure values in the TP50 group were higher than those in the epinephrine group at T10 (165 vs. 112 mmHg), T20 (160 vs. 82 mmHg), T30 (143 vs. 66 mmHg), T45 (119 vs. 67 mmHg) and T60 (96 vs. 66.8 mmHg). The blood lactate level was lower in the naloxone group than in the epinephrine group at T10 (5.15 vs. 10.5 mmol/L), T30 (2.57 vs. 5.24 mmol/L) and T60 (2.1 vs. 4.1 mmol/L).

CONCLUSIONS

In this rat model of asphyxia-induced cardiac arrest, terlipressin and naloxone were effective vasopressors in cardiopulmonary resuscitation and presented better metabolic profiles than epinephrine. Terlipressin provided better hemodynamic stability than epinephrine.

[Septic shock. Update of treatment using hypertonic saline and antidiuretic hormone-vasopressin]

Safety in the use of small volumes of hypertonic saline solution for hypovolaemic shock and in the treatment of intracranial hypertension has been demonstrated in studies in the field of resuscitation. There is little experience of this for septic shock in humans. Beneficial immunomodulatory effects have been detected in pre-clinical studies. Interactions with the pituitary-adrenal axis and with the secretion of anti-diuretic hormone are varied and suggestive, but are not sufficiently understood. On the other hand, vasopressin has cardiovascular, osmoregulatory, and coagulation effects, and also acts on the hypothalamic-pituitary-adrenal axis. There is a relative deficit of vasopressin in septic shock. Its use in these patients does not seem to have any advantages as regards mortality, but may be beneficial in patients at risk from acute renal failure, or those who receive corticosteroids. Terlipressin is a vasopressin analogue that has also been studied. The synergy between vasopressin and hypertonic saline is a hypothesis that is mainly supported in pre-clinical studies. The use of hypertonic saline solution in septic shock, although promising, is still experimental, and must be restricted to the field of controlled clinical trials.

The effects of terlipressin on regional hemodynamics and kidney function in experimental hyperdynamic sepsis

Background and Aims

Although terlipressin (TP) may improve renal function in cirrhotic patients, its use in sepsis remains controversial due to concerns about regional ischemia. We investigated the effects of TP on regional hemodynamics and kidney function in experimental hyperdynamic sepsis.

Methods

We studied thirteen merino ewes in a university physiology laboratory using a randomized controlled cross over design. We implanted flow probes around the pulmonary, circumflex coronary, superior mesenteric, renal and iliac arteries. We injected live Escherichia coli and induced hyperdynamic sepsis. We treated animals with either bolus vehicle or a single dose of TP (sTP = 1 mg). In a second group, after 1 mg of TP, two additional bolus injections (mTP) of 0.5 mg were given at 2 hourly intervals.

Main Results

sTP (1 mg) significantly increased mean arterial pressure (MAP) (74 to 89 mmHg; P<0.0001) creatinine clearance (31 to 85 mL/min; P<0.0001) and urine output (24 to 307 mL/hr) (P<0.0001). However, it decreased CO (5.7 to 3.9 L/min; p<0.0001), coronary blood flow (CBF) (43 to 32 mL/min; p<0.0001) and mesenteric blood flow (MBF) (944 to 625 mL/min; p = 0.004) and increased blood lactate (2.1 to 4.0 mmol/L; p<0.0001). Extra doses of TP caused little additional effect.

Conclusions

In hyperdynamic sepsis, bolus TP transiently improves MAP and renal function, but reduces CO, CBF and MBF, and increases blood lactate. Caution should be applied when prescribing bolus TP in septic patients at risk of coronary or mesenteric ischemia.

Vasopressin and Terlipressin in the Treatment of Vasodilatory Septic Shock: A Systematic Review

Background:

Vasodilatory septic shock unresponsive to fluid resuscitation requires the addition of vasopressors. Catecholamines remain the first line vasopressor therapy, but treatment failure is a potential problem. Vasopressin and its analogue, terlipressin, have been used for this indication.

Objective:

This systematic review aims to evaluate the effects of vasopressin and terlipressin on mortality and morbidity outcomes in patients with vasodilatory shock. Secondary outcomes include the effects of vasopressin and terlipressin on haemodynamic stability and organ function.

Method:

A computerised search of MEDLINE from January 1966 till June 2010 and screening of references of relevant articles were conducted. Only prospective, randomised controlled trials comparing vasopressin or terlipressin versus standard vasopressors or placebo were included.

Results:

Seven studies using vasopressin, three using terlipressin and one using both were identified. Four vasopressin trials assessing mortality and morbidity outcomes showed a trend towards benefit for mortality in adults but possibly adverse outcomes in a small paediatric study. No data was available on the long-term mortality and morbidity outcomes of terlipressin. Vasopressin and terlipressin were similar to standard vasopressors in maintaining haemodynamic parameters, while allowing a beneficial catecholamine-sparing effect. These agents also had a neutral to positive effect on organ function.

Conclusion:

Vasopressin and terlipressin was comparable to conventional agents in the maintenance of haemodynamic stability and organ function in vasodilatory shock. Since morbidity and mortality data do not differentiate vasopressin and terlipressin from catecholamines, their role remains unclear. More large studies evaluating the long-term outcomes in this group of patients are required.

Hepatorenal syndrome in the intensive care unit

Hepatorenal syndrome (HRS) is a functional form of acute kidney injury (AKI) associated with advanced liver cirrhosis or fulminant hepatic failure. Various new concepts have emerged since the initial diagnostic criteria and definition of HRS was initially published. These include better understanding of the pathophysiological mechanisms involved in HRS, identification of bacterial infection (especially spontaneous bacterial peritonitis) as the most important HRS-precipitating event, recognition that insufficient cardiac output plays a role in the occurrence of HRS, and evidence that renal failure reverses with pharmacotherapy. Patients with HRS are often critically ill and, by definition, have multiorgan failure. The purpose of this review is to provide an update on novel advances in HRS, with emphasis on the different aspects of management of these patients in the intensive care unit.

Bench-to-bedside review: Vasopressin in the management of septic shock

This review of vasopressin in septic shock differs from previous reviews by providing more information on the physiology and pathophysiology of vasopressin and vasopressin receptors, particularly because of recent interest in more specific AVPR1a agonists and new information from the Vasopressin and Septic Shock Trial (VASST), a randomized trial of vasopressin versus norepinephrine in septic shock. Relevant literature regarding vasopressin and other AVPR1a agonists was reviewed and synthesized. Vasopressin, a key stress hormone in response to hypotension, stimulates a family of receptors: AVPR1a, AVPR1b, AVPR2, oxytocin receptors and purinergic receptors. Rationales for use of vasopressin in septic shock are as follows: first, a deficiency of vasopressin in septic shock; second, low-dose vasopressin infusion improves blood pressure, decreases requirements for norepinephrine and improves renal function; and third, a recent randomized, controlled, concealed trial of vasopressin versus norepinephrine (VASST) suggests low-dose vasopressin may decrease mortality of less severe septic shock. Previous clinical studies of vasopressin in septic shock were small or not controlled. There was no difference in 28-day mortality between vasopressin-treated versus norepinephrine-treated patients (35% versus 39%, respectively) in VASST. There was potential benefit in the prospectively defined stratum of patients with less severe septic shock (5 to 14 μg/minute norepinephrine at randomization): vasopressin may have lowered mortality compared with norepinephrine (26% versus 36%, respectively, P = 0.04 within stratum). The result was robust: vasopressin also decreased mortality (compared with norepinephrine) if less severe septic shock was defined by the lowest quartile of arterial lactate or by use of one (versus more than one) vasopressor at baseline. Other investigators found greater hemodynamic effects of higher dose of vasopressin (0.06 units/minute) but also unique adverse effects (elevated liver enzymes and serum bilirubin). Use of higher dose vasopressin requires further evaluation of efficacy and safety. There are very few studies of interactions of therapies in critical care - or septic shock - and effects on mortality. Therefore, the interaction of vasopressin infusion, corticosteroid treatment and mortality of septic shock was evaluated in VASST. Low-dose vasopressin infusion plus corticosteroids significantly decreased 28-day mortality compared with corticosteroids plus norepinephrine (44% versus 35%, respectively, P = 0.03; P = 0.008 interaction statistic). Prospective randomized controlled trials would be necessary to confirm this interesting interaction. In conclusion, low-dose vasopressin may be effective in patients who have less severe septic shock already receiving norepinephrine (such as patients with modest norepinephrine infusion (5 to 15 μg/minute) or low serum lactate levels). The interaction of vasopressin infusion and corticosteroid treatment in septic shock requires further study.

Year in review 2009: Critical Care--shock

The research papers on shock that have been published in Critical Care throughout 2009 are related to four major subjects: first, alterations of heart function and, second, the role of the sympathetic central nervous system during sepsis; third, the impact of hemodynamic support using vasopressin or its synthetic analog terlipressin, and different types of fluid resuscitation; as well as, fourth, experimental studies on the treatment of acute respiratory distress syndrome. The present review summarizes the key results of these studies together with a brief discussion in the context of the relevant scientific and clinical background published both in this and other journals.

The role of vasoactive agents in the resuscitation of microvascular perfusion and tissue oxygenation in critically ill patients

Purpose

The clinical use of vasoactive drugs is not only intended to improve systemic hemodynamic variables, but ultimately to attenuate derangements in organ perfusion and oxygenation during shock. This review aims (1) to discuss basic physiology with respect to manipulating vascular tone and its effect on the microcirculation, and (2) to provide an overview of available clinical data on the relation between vasoactive drugs and organ perfusion, with specific attention paid to recent developments that have enabled direct in vivo observation of the microcirculation and concepts that have originated from it.

Methods

A MedLine search was conducted for clinical articles in the English language over the last 15 years pertainig to shock, sepsis, organ failure, or critically ill patients in combination with vasoactive drugs and specific variables of organ perfusion/oxygenation (e.g., tonometry, indocyanine clearance, laser Doppler, and sidestream dark field imaging).

Results

Eighty original papers evaluating the specific relationship between organ perfusion/oxygenation and the use of vasoactive drugs were identified and are discussed in light of physiological theory of vasomotor tone.

Conclusions

Solid clinical data in support of the idea that increasing blood pressure in shock improves microcirculatory perfusion/oxygenation seem to be lacking, and such a concept might not be in line with physiological theory of microcirculation as a low-pressure vascular compartment. In septic shock no beneficial effect on microcirculatory perfusion above a mean arterial pressure of 65 mmHg has been reported, but a wide range in inter-individual effect seems to exist. Whether improvement of microcirculatory perfusion is associated with better patient outcome remains to be elucidated.

[Terlipressin as rescue therapy in hypercyanotic spells of Fallot tetralogy]

Hypercyanotic spells, very common in Fallot tetralogy, are a medical emergency and can cause neurological damage or even death. They are produced by a dramatic decrease in pulmonary blood flow, with increased right-left shunt and a drop in systemic arterial saturation. Treatment includes alpha.-agonists (such as methoxamine or phenylephrine), which increase peripheral resistance, forcing the entry of blood through the infundibulum. However, they are not available in our environment. An alternative, still not described, could be terlipressin, a potent vasoconstrictor. We report a three months old infant, with Fallot tetralogy and hypoplastic pulmonary branches, who developed a severe hypoxaemic crisis during postoperative palliative surgery (Blalock-Taussig), no responsive to standard therapy. The administration of terlipressin in three hypercyanotic spells, was effective and reversed them, with a significant and sustained increase in arterial saturation. Although there is still no evidence, terlipressin may be an alternative to alpha.-agonists in these patients.

A role for BK channels in heart rate regulation in rodents

The heart generates and propagates action potentials through synchronized activation of ion channels allowing inward Na(+) and Ca(2+) and outward K(+) currents. There are a number of K(+) channel types expressed in the heart that play key roles in regulating the cardiac cycle. Large conductance calcium-activated potassium (BK) ion channels are not thought to be directly involved in heart function. Here we present evidence that heart rate can be significantly reduced by inhibiting the activity of BK channels. Agents that specifically inhibit BK channel activity, including paxilline and lolitrem B, slowed heart rate in conscious wild-type mice by 30% and 42%, respectively. Heart rate of BK channel knock-out mice (Kcnma1(-/-)) was not affected by these BK channel inhibitors, suggesting that the changes to heart rate were specifically mediated through BK channels. The possibility that these effects were mediated through BK channels peripheral to the heart was ruled out with experiments using isolated, perfused rat hearts, which showed a significant reduction in heart rate when treated with the BK channel inhibitors paxilline (1 microM), lolitrem B (1 microM), and iberiotoxin (0.23 microM), of 34%, 60%, and 42%, respectively. Furthermore, paxilline was shown to decrease heart rate in a dose-dependent manner. These results implicate BK channels located in the heart to be directly involved in the regulation of heart rate.

Investigational vasopressin receptor modulators in the pipeline

The vasopressin system is complex and interacts with the central nervous, cardiovascular, renal, and hematological systems. Vasopressin plays an important role in the control of blood osmolarity and vascular tone, but is also involved in many other physiological events, which are mediated mainly via three types of vasopressin receptor: V1R, V2R, and V3R. V1R primarily mediate the vascular, and V2R the aquaretic, effects of vasopressin. Vasopressin may also interact with other receptors, like adrenergic and angiotensin-II receptors, or with distinct biological pathways, including those of nitric oxide and the K(ATP) channel. There are numerous clinical situations where vasopressin receptor modulators (agonists or antagonists) could be used. Currently, vasopressin and terlipressin are most commonly used to stimulate V1R in vasodilatory shock and cardiac arrest, while desmopressin, a synthetic analogue of vasopressin, acts on V2R; but new molecules are becoming available in the treatment of inappropriate antidiuretic hormone (ADH) secretion.

Terlipressin: a promising vasoactive agent in hemodynamic support of septic shock

BACKGROUND

At present, terlipressin is predominantly used for the management of bleeding gastric and esophageal varices, as well as hepato-renal syndrome secondary to liver cirrhosis. Owing to its high and relatively selective affinity to vascular V1 receptors, terlipressin is also increasingly used as an adjunct vasopressor agent in the management of vasodilatory hyperdynamic septic shock.

OBJECTIVE

This review article aims to summarize the available knowledge related to hemodynamic support with terlipressin in septic shock.

METHODS

For literature search, PubMed and specific keywords from the MeSH Database were used.

RESULTS/CONCLUSIONS

Terlipressin represents an effective pressor agent in patients with catecholamine-unresponsive septic shock. However, caution should be exercised, as terlipressin may contribute dose-dependently to vasoconstriction and a reflectory decrease in cardiac output. Additional studies are needed to clarify: i) the optimal time of therapy institution; ii) the efficacy and the dosages of continuous infusion versus bolus administration; and iii) the safety and efficacy of this compound in comparison with other nonspecific vasopressinergic drugs, such as arginine vasopressin. Whether or not terlipressin may improve the outcome of septic shock patients compared with standard therapy with catecholamines remains to be determined.

Terlipressin or europressin?

Use of terlipressin in septic shock relies on a series of European studies resulting in a better knowledge of this vasopressive agent. Additional studies demonstrate that this agent appears to have attractive properties when administered properly. In comparison to prior reports, continuous infusion of low-dose terlipressin seems superior when administered to septic animals. For the first time in humans, Morelli and colleagues compared this mode of administration with other vasopressors.