Non-peptide arginine-vasopressin antagonists: the vaptans

Cu(II)-Catalyzed Enantioselective Aza-Friedel-Crafts Reaction of 1-Naphthols and Electron-Rich Phenols with Isatin-Derived Ketimines

New chiral ligands could be obtained by introducing proline moieties and imidazoline moieties to binaphthyl skeletons. The chiral ligands exhibited balanced rigidity and flexibility which could allow the change of the conformations during the reactions on one hand, and could provide sufficient asymmetric induction on the other. The proline moiety could act as a linker connecting the binaphthyl skeletons and the imidazoline moieties as well as a coordinating group for the central metal, and the electronic and steric properties of the imidazoline groups could be carefully fine-tuned by the use of different substituents. In the presence of Cu(II) catalyst bearing such chiral ligands, aza-Friedel-Crafts reaction of 1-naphthols and electron-rich phenols with isatin-derived ketimines provided the desired products with good to excellent yields and up to 99 % ee. The reactions showed good scalability, and excellent ee could still be obtained when the reaction was carried out in gram-scale.

Efficacy and safety of postoperative preemptive use of tolvaptan for patients with cirrhosis undergoing hepatectomy for hepatocellular carcinoma

PURPOSE

Optimal choice of diuretics in perioperative management remains unclear in enhanced recovery after liver surgery. This study investigated the efficacy and safety of tolvaptan (oral vasopressin V2-receptor antagonist) in postoperative management of patients with liver injury and hepatocellular carcinoma.

METHODS

The patients clinically diagnosed with liver cirrhosis were included in this study. Clinical outcomes of 51 prospective cohort managed with a modified postoperative protocol using tolvaptan (validation group) were compared with 83 patients treated with a conventional management protocol (control group).

RESULTS

Postoperative urine output were significantly larger and excessive body weight increase were reduced with no impairment in renal function or serum sodium levels in the validation group. Although the total amount of discharge and trend of serum albumin level were not significantly different among the groups, global incidence of postoperative morbidity was less frequent (19.6% vs. 44.6%, P=0.005) and postoperative stay was significantly shorter (8 days vs.10 days, P=0.008) in the validation group compared with the control group.

CONCLUSIONS

Tolvaptan could be safely used for the patients with injured liver in postoperative management after hepatectomy and potentially advantageous in the era of enhanced recovery after surgery with its strong diuretic effect and better fluid management.

How should we treat acute kidney injury caused by renal congestion?

Decreased kidney function is associated with increased risk of cardiovascular events and mortality, and heart failure (HF) is a wellknown risk factor for renal dysfunction. Acute kidney injury (AKI) in patients with HF often is attributed to prerenal factors, such as renal hypoperfusion and ischemia as a result of decreased cardiac output. Another such factor is reduction of absolute or relative circulating blood volume, with the decrease in renal blood flow leading to renal hypoxia followed by a decrease in the glomerular filtration rate. However, renal congestion is increasingly being recognized as a potential cause of AKI in patients with HF. Increased central venous pressure and renal venous pressure lead to increased renal interstitial hydrostatic pressure and a reduction of the glomerular filtration rate. Both decreased kidney function and renal congestion have been shown to be important prognostic factors of HF, and adequate control of congestion is important for improving kidney function. Loop and thiazide diuretics are recommended as standard therapies to reduce volume overload. However, these agents are associated with worsening renal function even though they are effective for improving congestive symptoms. There is growing interest in tolvaptan, which can improve renal congestion by increasing excretion of free water and decreasing the required dose of loop diuretic, thereby improving kidney function. This review summarizes renal hemodynamics, the pathogenesis of AKI due to renal ischemia and renal congestion, and diagnosis and treatment options for renal congestion.

Hyponatremia and Cancer: From Bedside to Benchside

Hyponatremia is the most common electrolyte disorder encountered in hospitalized patients. This applies also to cancer patients. Multiple causes can lead to hyponatremia, but most frequently this electrolyte disorder is due to the syndrome of inappropriate antidiuresis. In cancer patients, this syndrome is mostly secondary to ectopic secretion of arginine vasopressin by tumoral cells. In addition, several chemotherapeutic drugs induce the release of arginine vasopressin by the hypothalamus. There is evidence that hyponatremia is associated to a more negative outcome in several pathologies, including cancer. Many studies have demonstrated that in different cancer types, both progression-free survival and overall survival are negatively affected by hyponatremia, whereas the correction of serum [Na⁺] has a positive effect on patient outcome. In vitro studies have shown that cells grown in low [Na⁺] have a greater proliferation rate and motility, due to a dysregulation in intracellular signalling pathways. Noteworthy, vasopressin receptors antagonists, which were approved more than a decade ago for the treatment of euvolemic and hypervolemic hyponatremia, have shown unexpected antiproliferative effects. Because of this property, vaptans were also approved for the treatment of polycystic kidney disease. In vitro evidence indicated that this family of drugs effectively counteracts proliferation and invasivity of cancer cells, thus possibly opening a new scenario among the pharmacological strategies to treat cancer.

Management of Hyponatremia in Heart Failure: Practical Considerations

Hyponatremia is commonly encountered in the setting of heart failure, especially in decompensated, fluid-overloaded patients. The pathophysiology of hyponatremia in patients with heart failure is complex, including numerous mechanisms: increased activity of the sympathetic nervous system and the renin-angiotensin-aldosterone system, high levels of arginine vasopressin and diuretic use. Symptoms are usually mild but hyponatremic encephalopathy can occur if there is an acute decrease in serum sodium levels. It is crucial to differentiate between dilutional hyponatremia, where free water excretion should be promoted, and depletional hyponatremia, where administration of saline is needed. An inappropriate correction of hyponatremia may lead to osmotic demyelination syndrome which can cause severe neurological symptoms. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. The aim of this review is to summarize the principal mechanisms involved in the occurrence of hyponatremia, to present the main guidelines for the treatment of hyponatremia, and to collect and analyze data from studies which target new treatment options, such as vaptans.

Vasopressin receptor antagonists: a patent summary (2018-2022)

INTRODUCTION

Arginine-vasopressin hormone (AVP) is a key regulator in many essential physiological processes. The effect of AVP is mediated through three receptors within the body, these are the G protein-coupled vasopressin receptors, namely V1a, V1b (also called V3), and V2. Numerous studies investigated the role of these receptors in certain pathological conditions; therefore, stimulation or inhibition of these receptors may be a treatment option in these diseases.

AREAS COVERED

In this manuscript, the authors summarize recent patent activity (2018-2022) associated with vasopressin receptor antagonists (selective V1a or V2, and dual-acting V1a/V2), focusing mostly on chemical structures, their modifications, and potential clinical applications. Patent search was carried out using SciFinder, Espacenet, Patentscope, Cortellis Competitive Intelligence, and Derwent Innovation databases.

EXPERT OPINION

In recent years, vasopressin receptor antagonists have been in the spotlight of drug discovery, especially V1a selective molecules. Publishing balovaptan as a possible treatment for autism spectrum disorder (ASD), greatly increased the interest in CNS-acting vasopressin antagonists. In addition, peripherally active selective V2 and dual-acting V1a/V2 antagonists have also been developed. Although clinical trials were unsuccessful in many cases, there is still potential in the research of vasopressin receptor antagonists as shown by several currently ongoing clinical trials.

The role of tolvaptan in pulmonary hypertension: A retrospective study

Pulmonary hypertension (PH) is a severe form of pulmonary vascular disease that can lead to right heart failure (RHF). Nearly 2-thirds of patients with PH die within 5 years. Studies suggest that a new diuretic medication, called tolvaptan (TLV), can be used to treat PH. However, there is still insufficient evidence to confirm its effectiveness. Therefore, we investigated the role of TLV in patients with PH. This retrospective study included 73 patients with PH hospitalized in Shanghai Pulmonary Hospital between November 2019 and March 2022. All patients received 7.5 to 15.0 mg of TLV for 3 to 21 days starting at admission, in addition to targeted drugs and traditional diuretic therapy. The outcomes included the blood pressure, urine and water intake volumes, electrolyte concentrations, and renal, liver, and cardiac function indexes before and after TLV treatment. In addition, we assessed the clinical symptoms and adverse reactions during the treatment. After TLV treatment, the water intake and urine volumes significantly increased, and body weight, diastolic blood pressure (DBP) and mean arterial pressure significantly decreased. Total bilirubin, direct bilirubin, N-terminal pro-brain natriuretic peptide, and serum uric acid (UA) levels after TLV treatment were significantly lower than before treatment. After TLV treatment, dyspnea significantly improved in 71 of 73 patients, and lower limb edema disappeared in 42 of 53 patients. No obvious adverse reactions occurred during the TLV treatment period. These results suggest that adding TLV to targeted drug and traditional diuretic therapies is effective for patients with PH. However, more data are required to support these findings.

Chiral Phosphoric Acid-Catalyzed Enantioselective Aza-Friedel-Crafts Addition of Naphthols with Isatin-Derived Ketimines

The enantioselective Friedel-Crafts addition of naphthols with isatin-derived ketimines was developed with H₈-BINOL-derived chiral biaryl phosphoric acid. A wide range of isatin-derived ketimines and naphthols were successfully applied and gave a series of chiral 3-amino-2-oxindoles in excellent yields with high optical purities.

Hyponatremia and Liver Transplantation: A Narrative Review

Hyponatremia is a common electrolyte disorder in patients with end-stage liver disease (ESLD) and is associated with increased mortality on the liver transplantation (LT) waiting list. The impact of hyponatremia on outcomes after LT is unclear. Ninety-day and one-year mortality may be increased, but the data are conflicting. Hyponatremic patients have an increased rate of complications and longer hospital stays after transplant. Although rare, osmotic demyelination syndrome (ODS) is a feared complication after LT in the hyponatremic patient. The condition may occur when the serum sodium (sNa) concentration increases excessively during or after LT. This increase in sNa concentration correlates with the degree of preoperative hyponatremia, the amount of intraoperative blood loss, and the volume of intravenous fluid administration. The risk of developing ODS after LT can be mitigated by avoiding large perioperative increases in sNa concentration . This can be achieved through measures such as carefully increasing the sNa pretransplant, and by limiting the intravenous intra- and postoperative amounts of sodium infused. SNa concentrations should be monitored regularly throughout the entire perioperative period.

Clinical, Genetic and Functional Characterization of a Novel AVPR2 Missense Mutation in a Woman with X-Linked Recessive Nephrogenic Diabetes Insipidus

Nephrogenic diabetes insipidus (NDI) is a rare disorder characterized by renal unresponsiveness to the hormone vasopressin, leading to excretion of large volumes of diluted urine. Mutations in the arginine vasopressin receptor-2 (AVPR2) gene cause congenital NDI and have an X-linked recessive inheritance. The disorder affects almost exclusively male family members, but female carriers occasionally present partial phenotypes due to skewed inactivation of the X-chromosome. Here, we report a rare case of a woman affected with X-linked recessive NDI, presenting an average urinary output of 12 L/day. Clinical and biochemical studies showed incomplete responses to water deprivation and vasopressin stimulation tests. Genetic analyses revealed a novel heterozygous missense mutation (c.493G > C, p.Ala165Pro) in the AVPR2 gene. Using a combination of in-silico protein modeling with human cellular models and molecular phenotyping, we provide functional evidence for phenotypic effects. The mutation destabilizes the helical structure of the AVPR2 transmembrane domains and disrupts its plasma membrane localization and downstream intracellular signaling pathways upon activation with its agonist vasopressin. These defects lead to deficient aquaporin 2 (AQP2) membrane translocation, explaining the inability to concentrate urine in this patient.

Prediction of molecular interactions and physicochemical properties relevant for vasopressin V2 receptor antagonism

We have developed two ligand- and receptor-based computational approaches to study the physicochemical properties relevant to the biological activity of vasopressin V2 receptor (V2R) antagonist and eventually to predict the expected binding mode to V2R. The obtained quantitative structure activity relationship (QSAR) model showed a correlation of the antagonist activity with the hydration energy (E_H2O), the polarizability (P), and the calculated partial charge on atom N7 (q6) of the common substructure. The first two descriptors showed a positive contribution to antagonist activity, while the third one had a negative contribution. V2R was modeled and further relaxed on a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocoline (POPC) membrane by molecular dynamics simulations. The receptor antagonist complexes were guessed by molecular docking, and the stability of the most relevant structures was also evaluated by molecular dynamics simulations. As a result, amino acid residues Q96, W99, F105, K116, F178, A194, F307, and M311 were identified with the probably most relevant antagonist-receptor interactions on the studied complexes. The proposed QSAR model could explain the molecular properties relevant to the antagonist activity. The contributions to the antagonist-receptor interaction appeared also in agreement with the binding mode of the complexes obtained by molecular docking and molecular dynamics. These models will be used in further studies to look for new V2R potential antagonist molecules.

Recent advances of fluorescent biosensors based on cyclic signal amplification technology in biomedical detection

The cyclic signal amplification technology has been widely applied for the ultrasensitive detection of many important biomolecules, such as nucleic acids, proteins, enzymes, adenosine triphosphate (ATP), metal ions, exosome, etc. Due to their low content in the complex biological samples, traditional detection methods are insufficient to satisfy the requirements for monitoring those biomolecules. Therefore, effective and sensitive biosensors based on cyclic signal amplification technology are of great significance for the quick and simple diagnosis and treatment of diseases. Fluorescent biosensor based on cyclic signal amplification technology has become a research hotspot due to its simple operation, low cost, short time, high sensitivity and high specificity. This paper introduces several cyclic amplification methods, such as rolling circle amplification (RCA), strand displacement reactions (SDR) and enzyme-assisted amplification (EAA), and summarizes the research progress of using this technology in the detection of different biomolecules in recent years, in order to provide help for the research of more efficient and sensitive detection methods.

Prediction factors of tolvaptan effectiveness in patients with refractory ascites complicated with hepatocellular carcinoma

OBJECTIVE

Tolvaptan (TVP) is an effective treatment for patients with cirrhotic ascites; however, studies have indicated that a sufficient effect is difficult to obtain in patients with hepatocellular carcinoma (HCC). This study evaluates the efficacy of TVP in patients with HCC with refractory ascites.

METHODS

We retrospectively enrolled 32 patients with liver cirrhosis and refractory ascites [mean age: 74 years (range, 47-86 years), men: 78.1% (25/32)]. All patients had HCC and were treated with TVP at our hospital. A TVP responder was defined as a patient who experienced decrease in body weight by ≥1.5 kg within 1 week of treatment. Univariate and multivariate analyses were performed to evaluate clinical and laboratory predictive factors of TVP response.

RESULTS

The TVP response rate was 46.9% (15/32 patients) after 1 week of treatment. HCC treatment (transcatheter arterial chemoembolization and/or radiofrequency ablation) was administered to 11/15 (73.3%) responders. In the multivariate analysis, the reduction of urine osmolality was higher in responders than nonresponders (202 mOsm/l vs. 65 mOsm/l, P = 0.040), and the tumor stage (P = 0.043) was worse in nonresponders. Multivariate Cox proportional hazards regression analysis indicated a significantly better prognosis among responders than among nonresponders (P < 0.01).

CONCLUSION

The HCC tumor stage and the reduction in urine osmolality can predict the efficacy of TVP in patients with refractory ascites complicated with HCC. TVP may allow therapeutic intervention for HCC and improve prognosis, even in patients with Child-Pugh class C.

Management of Ascites in Patients with Cirrhosis: An Update

Ascites represents a critical event in the natural history of liver cirrhosis. From a prognostic perspective, its occurrence marks the transition from the compensated to the decompensated stage of the disease, leading to an abrupt worsening of patients' life expectancy. Moreover, ascites heralds a turbulent clinical course, characterized by acute events and further complications, frequent hospitalizations, and eventually death. The pathophysiology of ascites classically relies on hemodynamic mechanisms, with effective hypovolemia as the pivotal event. Recent discoveries, however, integrated this hypothesis, proposing systemic inflammation and immune system dysregulation as key mechanisms. The mainstays of ascites treatment are represented by anti-mineralocorticoids and loop diuretics, and large volume paracentesis. When ascites reaches the stage of refractoriness, however, diuretics administration should be cautious due to the high risk of adverse events, and patients should be treated with periodic execution of paracentesis or with the placement of a trans-jugular intra-hepatic portosystemic shunt (TIPS). TIPS reduces portal hypertension, eases ascites control, and potentially modify the clinical course of the disease. Further studies are required to expand its indications and improve the management of complications. Long-term human albumin administration has been studied in two RCTs, with contradictory results, and remains a debated issue worldwide, despite a potential effectiveness both in ascites control and long-term survival. Other treatments (vaptans, vasoconstrictors, or implantable drainage systems) present some promising aspects but cannot be currently recommended outside clinical protocols or a case-by-case evaluation.

Clinical features and long-term prognosis of patients with congestive heart failure taking tolvaptan: a comparison of patients with preserved and reduced left ventricular ejection fraction

Few studies have investigated the clinical benefit of the long-term use of tolvaptan (TLV) for heart failure (HF). This study evaluated the long-term prognosis of patients administered TLV for > 1 year among patients who had HF with preserved ejection fraction (HFpEF) and those who had HF with reduced ejection fraction (HFrEF). Overall, 591 consecutive patients were admitted to our hospital and administered TLV for HF between 2011 and 2018. We retrospectively enrolled 147 patients who were administered TLV for > 1 year. We divided them into the HFpEF group (n = 77, 52.4%) and the HFrEF group (n = 70; 47.6%). Their clinical backgrounds and long-term prognosis were examined. Compared with the patients in the HFrEF group, the patients in the HFpEF group were significantly older and included more women. Moreover, the HFpEF group showed significantly lower all-cause mortality (38.6% vs. 24.7%; log-rank, P = 0.014) and cardiovascular mortality during the average 2.7-year follow-up. Univariate analysis revealed that all-cause mortality was correlated with male sex, HFpEF, and changes in serum creatinine levels from baseline. Multivariate analysis revealed that HFpEF was an independent influencing factor for all-cause mortality (hazard ratio, 0.44; 95% confidence interval, 0.23-0.86; P = 0.017). Long-term administration of TLV may be more beneficial for HFpEF than for HFrEF.

Management of Cirrhotic Ascites under the Add-on Administration of Tolvaptan

Tolvaptan is a recently available diuretic that blocks arginine vasopressin receptor 2 in the renal collecting duct. Its diuretic mechanism involves selective water reabsorption by affecting the water reabsorption receptor aquaporin 2. Given that liver cirrhosis patients exhibit hyponatremia due to their pseudo-aldosteronism and usage of natriuretic agents, a sodium maintaining agent, such as tolvaptan, is physiologically preferable. However, large scale studies indicating the patients for whom this would be effective and describing management under its use have been insufficient. The appropriate management of cirrhosis patients treated with tolvaptan should be investigated. In the present review, we collected articles investigating the effectiveness of tolvaptan and factors associated with survival and summarized their management reports. Earlier administration of tolvaptan before increasing the doses of natriuretic agents is recommended because this may preserve effective arterial blood volume.

The Biology of Vasopressin

Vasopressins are evolutionarily conserved peptide hormones. Mammalian vasopressin functions systemically as an antidiuretic and regulator of blood and cardiac flow essential for adapting to terrestrial environments. Moreover, vasopressin acts centrally as a neurohormone involved in social and parental behavior and stress response. Vasopressin synthesis in several cell types, storage in intracellular vesicles, and release in response to physiological stimuli are highly regulated and mediated by three distinct G protein coupled receptors. Other receptors may bind or cross-bind vasopressin. Vasopressin is regulated spatially and temporally through transcriptional and post-transcriptional mechanisms, sex, tissue, and cell-specific receptor expression. Anomalies of vasopressin signaling have been observed in polycystic kidney disease, chronic heart failure, and neuropsychiatric conditions. Growing knowledge of the central biological roles of vasopressin has enabled pharmacological advances to treat these conditions by targeting defective systemic or central pathways utilizing specific agonists and antagonists.

Rapid umpolung Michael addition of isatin N,N′-cyclic azomethine imine 1,3-dipoles with chalcones

3,3-Disubstituted oxindoles were prepared rapidly in moderate to excellent yields with promising dr values by the t-BuONa-promoted Michael addition.

Palladium-catalyzed asymmetric allylic alkylation of 3-aminooxindoles to access chiral homoallylic aminooxindoles

An organometal catalytic conversion of 3-aminooxindoles for the diastereo- and enantioselective synthesis of homoallylic aminooxindoles has been described. The asymmetric allylic alkylation of 3-aminooxindoles with allyl carboxylates proceeded smoothly to afford a series of chiral 3-allyl-3-aminooxindoles. This work offers an alternative route to build these scaffolds. The application of this protocol is also highlighted by a significant conversion of products to the potential applicable spiro[indoline-3,2'-pyrrolidin]-2-one derivatives.

Tolvaptan reduces the required amount of albumin infusion in patients with decompensated cirrhosis with uncontrolled ascites : a multicenter retrospective propensity score-matched cohort study

Background

The aim of this retrospective study was to determine whether tolvaptan treatment reduces the amount of albumin administered, volume of ascites removed, and frequency of paracentesis procedures in patients with decompensated cirrhosis with uncontrolled ascites with conventional diuretics.

Patients and methods

The control (C) group included patients treated with conventional diuretics. The tolvaptan (T) group included patients treated with both tolvaptan and conventional diuretics. Both groups were matched according to baseline parameters. The amount of albumin administered, volume of ascites removed, and frequency of paracentesis within 30 days of onset of uncontrolled ascites were compared between the two groups.

Results

After matching, 74 patients (C=37, T=37) were included. Baseline parameters (C vs. T group) were as follows: age, 69.5 ± 9.3 vs. 70.4 ± 11.0 years (p = 0.702) ; males, 24 (64.9%) vs. 25 (67.6%) (p = 0.999) ; patients with hepatocellular carcinoma, 17 (45.9%) vs. 18 (48.6%) (p = 0.999) ; serum albumin levels at treatment initiation, 2.76 ± 0.48 vs. 2.73 ± 0.49 g/dL (p = 0.773), and serum creatinine levels at treatment initiation, 1.18 ± 1.23 vs. 1.09 ± 0.48 g/dL (p = 0.679). In the C vs. T groups, respectively, mean amount of albumin administered was 51.0 ± 31.4 vs. 33.4 ± 29.8 g/month (p = 0.016) ; mean volume of ascites removed was 2,905 ± 4,921 vs. 1,824 ± 3,185 mL/month (p = 0.266) ; and mean frequency of paracentesis was 0.92 ± 1.46 vs. 0.89 ± 1.45 procedures (p = 0.937).

Conclusions

Tolvaptan reduced the use of albumin infusion in patients with decompensated cirrhosis and was effective and acceptable for uncontrolled ascites.

Case Report: Long-Term Tolvaptan Treatment in a Child With SIADH and Suprasellar Arachnoid Cyst

Suprasellar arachnoid cysts represent a rare occurrence in the pediatric population and usually cause symptoms related to mass effect and can occasionally cause endocrine dysfunctions. The association between SAC and the syndrome of inappropriate antidiuretic hormone (SIADH) in the pediatric population has rarely been described previously. In most cases, SIADH is temporary and resolves by treating the underlying cause. The first-line treatment consists of fluid restriction in asymptomatic children. Oral urea and demeclocycline are other effective treatment options. Vaptans are a new class of medication for the management of SIADH. These agents are a nonpeptide vasopressin V2 receptor antagonist that selectively antagonizes the antidiuretic effect of AVP, resulting in excretion of diluted urine or "aquaresis." Their efficacy has been shown in adult patients with euvolemic or hypervolemic hyponatremia. However, evidence is lacking in pediatric patients with SIADH. We report the case of a 9-year-old female child with a SAC, who underwent endoscopic fenestration at the age of 2 years. After surgery she developed chronic hyponatremia due to SIADH. Hyponatremia was refractory to treatment with fluid restriction, oral sodium, and urea. In order to normalize serum sodium levels, tolvaptan treatment was started on a compassionate-use basis; 24-48 h later serum sodium levels returned to normal. To date, tolvaptan has been used regularly for 6 years with no side effects occurring during the treatment period. This is the first case of a child with chronic SIADH secondary to SAC successfully treated with tolvaptan. Further studies are needed to demonstrate its usefulness on a broader case series.

Guidelines on the management of ascites in cirrhosis

The British Society of Gastroenterology in collaboration with British Association for the Study of the Liver has prepared this document. The aim of this guideline is to review and summarise the evidence that guides clinical diagnosis and management of ascites in patients with cirrhosis. Substantial advances have been made in this area since the publication of the last guideline in 2007. These guidelines are based on a comprehensive literature search and comprise systematic reviews in the key areas, including the diagnostic tests, diuretic use, therapeutic paracentesis, use of albumin, transjugular intrahepatic portosystemic stent shunt, spontaneous bacterial peritonitis and beta-blockers in patients with ascites. Where recent systematic reviews and meta-analysis are available, these have been updated with additional studies. In addition, the results of prospective and retrospective studies, evidence obtained from expert committee reports and, in some instances, reports from case series have been included. Where possible, judgement has been made on the quality of information used to generate the guidelines and the specific recommendations have been made according to the 'Grading of Recommendations Assessment, Development and Evaluation (GRADE)' system. These guidelines are intended to inform practising clinicians, and it is expected that these guidelines will be revised in 3 years' time.

Natremia and liver transplantation: The right amount of salt for a good recipe

An adequate balance between electrolytes and clear water is of paramount importance to maintaining physiologic homeostasis. Natremia imbalance and, in particular, hyponatremia is the most frequent electrolyte abnormality observed in hospitalized subjects, involving approximately one-fourth of them. Pathological changes occurring during liver cirrhosis predispose patients to an increased risk of sodium imbalance, and hypervolemic hyponatremia has been reported in nearly 50% of subjects with severe liver disease and ascites. Splanchnic vasodilatation, portal-systemic collaterals’ opening and increased excretion of vasoactive modulators are all factors impairing clear water handling during liver cirrhosis. Of concern, sodium imbalance has been consistently reported to be associated with increased risk of complications and reduced survival in liver disease patients. In the last decades clinical interest in sodium levels has been also extended in the field of liver transplantation. Evidence that [Na⁺] in blood is an independent risk factor for in-list mortality led to the incorporation of sodium value in prognostic scores employed for transplant priority, such as model for end-stage liver disease-Na and UKELD. On the other hand, severe hyponatremic cirrhotic patients are frequently delisted by transplant centers due to the elevated risk of mortality after grafting. In this review, we describe in detail the relationship between sodium imbalance and liver cirrhosis, focusing on its impact on peritransplant phases. The possible therapeutic approaches, in order to improve transplant outcome, are also discussed. 

Investigating the Multitarget Mechanism of Traditional Chinese Medicine Prescription for Cancer-Related Pain by Using Network Pharmacology and Molecular Docking Approach

Gu-tong formula (GTF) has achieved good curative effects in the treatment of cancer-related pain. However, its potential mechanisms have not been explored. We used network pharmacology and molecular docking to investigate the molecular mechanism and the effective compounds of the prescription. Through the analysis and research in this paper, we obtained 74 effective compounds and 125 drug-disease intersection targets to construct a network, indicating that quercetin, kaempferol, and β-sitosterol were possibly the most important compounds in GTF. The key targets of GTF for cancer-related pain were Jun proto-oncogene (JUN), mitogen-activated protein kinase 1 (MAPK1), and RELA proto-oncogene (RELA). 2204 GO entries and 148 pathways were obtained by GO and KEGG enrichment, respectively, which proved that chemokine, MAPK, and transient receptor potential (TRP) channels can be regulated by GTF. The results of molecular docking showed that stigmasterol had strong binding activity with arginine vasopressin receptor 2 (AVPR2) and C-X3-C motif chemokine ligand 1 (CX3CL1) and cholesterol was more stable with p38 MAPK, prostaglandin-endoperoxide synthase 2 (PTGS2), and transient receptor potential vanilloid-1 (TRPV1). In conclusion, the therapeutic effect of GTF on cancer-related pain is based on the comprehensive pharmacological effect of multicomponent, multitarget, and multichannel pathways. This study provides a theoretical basis for further experimental research in the future.

Arginine vasopressin receptor 1a is a therapeutic target for castration-resistant prostate cancer

Castration-resistant prostate cancer (CRPC) recurs after androgen deprivation therapy (ADT) and is incurable. Reactivation of androgen receptor (AR) signaling in the low androgen environment of ADT drives CRPC. This AR activity occurs through a variety of mechanisms, including up-regulation of AR coactivators such as VAV3 and expression of constitutively active AR variants such as the clinically relevant AR-V7. AR-V7 lacks a ligand-binding domain and is linked to poor prognosis. We previously showed that VAV3 enhances AR-V7 activity to drive CRPC progression. Gene expression profiling after depletion of either VAV3 or AR-V7 in CRPC cells revealed arginine vasopressin receptor 1a (AVPR1A) as the most commonly down-regulated gene, indicating that this G protein-coupled receptor may be critical for CRPC. Analysis of publicly available human PC datasets showed that AVPR1A has a higher copy number and increased amounts of mRNA in advanced PC. Depletion of AVPR1A in CRPC cells resulted in decreased cell proliferation and reduced cyclin A. In contrast, androgen-dependent PC, AR-negative PC, or nontumorigenic prostate epithelial cells, which have undetectable AVPR1A mRNA, were minimally affected by AVPR1A depletion. Ectopic expression of AVPR1A in androgen-dependent PC cells conferred castration resistance in vitro and in vivo. Furthermore, treatment of CRPC cells with the AVPR1A ligand, arginine vasopressin (AVP), activated ERK and CREB, known promoters of PC progression. A clinically safe and selective AVPR1A antagonist, relcovaptan, prevented CRPC emergence and decreased CRPC orthotopic and bone metastatic growth in mouse models. Based on these preclinical findings, repurposing AVPR1A antagonists is a promising therapeutic approach for CRPC.

Organocatalytic Enantioselective Michael Addition between 3-(3-hydroxy-1H-pyrazol-1-yl)Oxindole and β-Nitrostyrene for the Preparation of Chiral Disubstituted Oxindoles

A new enantioselective Michael addition between 3-(3-hydroxy-1H-pyrazol-1-yl)oxindole, a new synthon generated from isatin N,N'-cyclic azomethine imine 1,3-dipole, and β-nitrostyrene has been disclosed. A series of chiral 3-(3-oxo-2,3-dihydro-1H-pyrazol-1-yl) disubstituted oxindoles were obtained in excellent results (up to 97% yield, up to 94% ee) with moderate to good diastereoselectivities (up to 4.3:1 dr).

Tolvaptan therapy to treat severe hyponatremia in pediatric nephrotic syndrome

BACKGROUND

Tolvaptan is a selective oral vasopressin V2-receptor antagonist. Some data have implicated stimulation of arginine vasopressin (AVP) as an important factor in oedema formation in a rodent model of nephrotic syndrome (NS) and adult NS patients. We report case of pediatric NS with severe hyponatremia efficiently treated by tolvaptan.

CASE/DIAGNOSIS - TREATMENT

A 22-month-old girl presented first with NS. She remained nephrotic after a 30-day course of oral steroids. Tacrolimus was inefficient and there was no response to plasma exchanges (15 sessions on a daily basis). She had severe oedema and ascites. Thus, in addition to immunosuppressive therapy, she received diuretics, furosemide 5 mg/kg/day, and amiloride 1 mg/kg/day, and required water restriction. She was hypertensive and was treated with a full dose of calcium inhibitor (amlodipine 0.5 mg/kg/day). After2 months of treatment, serum sodium reached 116 mmol/L and urinary osmolarity 547 mosmol/L, suggesting an inappropriate AVP secretion. Tolvaptan was introduced at 0.3 mg/kg/day and progressively increased to 3 mg/kg/day on day 4, leading to a partial correction of serum sodium (130 mmol/l) and a urinary osmolarity decrease to 90 mosmol/L. Tolvaptan was then continued at the dose of 3 mg/kg/day with unchanged serum sodium, without hypernatremia or dehydration. Her weight decreased from 14.8 k to 14 k, but oedema still persisted.

CONCLUSION

Tolvaptan was very efficient in this case of hyponatremia associated with steroid-resistant NS. Tolvaptan should be considered in the management of therapy-resistant hyponatremia in patients with NS.

Tolvaptan add-on therapy in patients with acute heart failure: A systematic review and meta-analysis

This study aimed to investigate the short-term efficacy and safety of tolvaptan as an add-on to traditional diuretics in patients with acute heart failure (AHF). The PubMed, EMBASE, Cochrane Library, and Web of Science databases were comprehensively searched for all randomized controlled trials (RCTs) that examined AHF patients treated with tolvaptan as a combination therapy with traditional diuretics published on or before December 2, 2019. Efficacy indicators such as improved dyspnea, reduced edema, and changes in urine output and body weight were evaluated. In-hospital mortality and worsening renal function (WRF) were measured as safety indicators. Data from the published literature included in this study were independently extracted by two reviewers. The Cochrane risk of bias tool was used to evaluate the quality of the included RCTs. Twelve RCTs involving 5577 patients admitted for AHF were included. Compared with traditional diuretics alone, add-on tolvaptan significantly relieved dyspnea, reduced weight, increased total urine volume and changes in urine volume from baseline, reduced edema, and increased serum sodium concentration in the short term without increasing the mortality. Most importantly, a low dose of tolvaptan (7.5-15 mg/d) significantly reduced the incidence of WRF, while a high dose (30 mg/d) had the opposite effect. Short-term add-on tolvaptan in hospitalized AHF patients could significantly relieve shortness of breath, reduce body weight, improve edema, and increase urine output and serum sodium concentrations without increasing mortality. The protective effects of add-on tolvaptan against WRF, however, were observed at low doses, but not at high doses.

Hypertonic saline, isotonic saline, water restriction, long loops diuretics, urea or vaptans to treat hyponatremia

Introduction: Hyponatremia is the most common fluid and electrolyte abnormality. It is associated with much higher morbidity and mortality rates than found in non hyponatremic patients.Areas covered: When the physician is faced to a hyponatremic patient he first has to confirm that hyponatremia is associated with hypoosmolality. Then he must answer to a series of questions: What is its origin? Is it acute or chronic? Which treatment is the most appropriate? We will discuss the various options for the treatment of hypotonic hyponatremia. For a better comprehensive approach of the treatment we will also discuss some pathophysiological data. The use of urea in euvolemic and hypervolemic hyponatremia will be particularly discussed. Literature was reviewed from Jan 1970 to Dec 2019.Expert opinion: Prospective studies showing the benefit in decreasing morbidity by increasing SNa in patients with chronic hyponatremia should be done. These studies should also compare the efficacy and side effects of urea therapy compare to vaptans.

Clinical implications with tolvaptan on monitored bioimpedance-defined fluid status in patients with cirrhotic ascites: an observational study

Background

Prognostic value or clinical implications of fluid status monitoring in liver cirrhosis are not fully elucidated. Tolvaptan, an orally available, selective vasopressin V2-receptor antagonist approved for hyponatremia in the United States and European Union. It is also used for cirrhotic ascites at a relatively low dose (3.75 mg to 7.5 mg) in Japan, exerts its diuretic function by excreting electrolyte-free water. We hypothesized that bioimpedance-defined dynamic changes in fluid status allow prediction of response of V2 antagonism and survival in cirrhotic patients.

Methods

In this prospective observational study, 30 patients with decompensated liver cirrhosis who were unresponsive to conventional diuretics were enrolled. Detailed serial changes of body composition that were assessed by using non-invasive bioimpedance analysis (BIA) devices, along with biochemical studies, were monitored at 5 time points.

Results

Sixteen patients were classified as short-term responders (53%). Rapid and early decrease of BIA-defined intracellular water, as soon as 6 h after the first dose (ΔICW_BIA%-6 h), significantly discriminated responders from non-responders (AUC = 0.97, P < 0.0001). ΔICW_BIA%-6 h was highly correlated with the change of BIA-derived phase angle of trunk, e.g. reduced body reactance operated at 50 kHz after 24 h of the first dose of tolvaptan. Lower baseline blood urea nitrogen and lower serum aldosterone were predictive of a rapid and early decrease of ICW_BIA. A rapid and early decrease of ICW_BIA in response to tolvaptan was also predictive of a better transplant-free survival.

Conclusions

BIA-defined water compartment monitoring may help predict short-term efficacy and survival in decompensated cirrhotic patients treated with tolvaptan.

Management of refractory ascites attenuates muscle mass reduction and improves survival in patients with decompensated cirrhosis

BACKGROUND

This study investigated time-course changes in skeletal muscle volume per year with tolvaptan in patients with refractory ascites that was unresponsive to loop diuretics and aldosterone antagonists.

METHODS

This retrospective study included 42 patients who received tolvaptan for refractory ascites and/or hepatic edema and underwent computed tomography (CT) before and ≥ 3 months after initiating tolvaptan. The time-course changes in skeletal muscle index per year [ΔSMI (%)] was calculated as follows: ΔSMI (%) = (SMI at final CT scan - SMI at initial CT scan)/SMI at initial CT scan × 100/years between CT scans.

RESULTS

Eligible patients were 23 men and 19 women of median age of 71 years (range 21-94 years). The median follow-up period was 22.7 (range 3.5-54.6) months. ΔSMI (%) was significantly higher in the responders group than in the nonresponder group. Multivariate analysis showed the response to tolvaptan was an independent and significant factor associated with an increase in muscle mass [odds ratio (OR) 20.364; 95% CI 2.327-178.97; P = 0.006]. Overall survival with tolvaptan was significantly higher in the responder group than in the nonresponder group. Multivariate analysis showed that the response to tolvaptan treatment was a significant contributor to good prognosis (OR 3.884; 95% CI 1.264-11.931; P = 0.018). A significant negative correlation was observed between the dosage of furosemide and ΔSMI (%) (P = 0.014).

CONCLUSIONS

Treatment of refractory ascites with tolvaptan may attenuate the progression of sarcopenia and improve the prognosis in patients with decompensated cirrhosis.

Enantioselective and regioselective aza-Friedel–Crafts reaction of electron-rich phenols with isatin-derived ketimines

An efficient asymmetric aza-Friedel–Crafts reaction of phenols with isatin-derived ketimines is described.

Lixivaptan, a New Generation Diuretic, Counteracts Vasopressin-Induced Aquaporin-2 Trafficking and Function in Renal Collecting Duct Cells

Vasopressin V2 receptor (V2R) antagonists (vaptans) are a new generation of diuretics. Compared with classical diuretics, vaptans promote the excretion of retained body water in disorders in which plasma vasopressin concentrations are inappropriately high for any given plasma osmolality. Under these conditions, an aquaretic drug would be preferable over a conventional diuretic. The clinical efficacy of vaptans is in principle due to impaired vasopressin-regulated water reabsorption via the water channel aquaporin-2 (AQP2). Here, the effect of lixivaptan—a novel selective V2R antagonist—on the vasopressin-cAMP/PKA signaling cascade was investigated in mouse renal collecting duct cells expressing AQP2 (MCD4) and the human V2R. Compared to tolvaptan—a selective V2R antagonist indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia—lixivaptan has been predicted to be less likely to cause liver injury. In MCD4 cells, clinically relevant concentrations of lixivaptan (100 nM for 1 h) prevented dDAVP-induced increase of cytosolic cAMP levels and AQP2 phosphorylation at ser-256. Consistent with this finding, real-time fluorescence kinetic measurements demonstrated that lixivaptan prevented dDAVP-induced increase in osmotic water permeability. These data represent the first detailed demonstration of the central role of AQP2 blockade in the aquaretic effect of lixivaptan and suggest that lixivaptan has the potential to become a safe and effective therapy for the treatment of disorders characterized by high plasma vasopressin concentrations and water retention.

Novel 3,3-disubstituted oxindole derivatives. Synthesis and evaluation of the anti-proliferative activity

3,3-Disubstituted oxindole derivatives bearing a nitrogen atom at the C-3 position have been synthesized starting from 3-alkyl oxindole through a metal free pathway. These derivatives have been tested in five human tumor cell lines (PC3, MCF7, SW620, MiaPaca2 and A375) and on primary cells (PBMCs) from healthy donors providing compound 6d showing a strong anticancer effect in all cancer lines on the low micromolar range.

Impact of Vaptans on Clinical Outcomes in Cirrhosis Patients: A Meta-Analysis of Randomized Controlled Trials

Background: Vaptans have been confirmed to mobilize ascites and improve hyponatremia in cirrhosis patients. However, the effects of vaptans on all-cause mortality, ascites-related complications, and adverse events in cirrhosis patients have not been fully determined.

Objectives: To systematically evaluate the impact of vaptans on the clinical outcomes in patients with cirrhosis.

Materials and Methods: A systematic review and meta-analysis was performed. The PubMed, Embase, and Cochrane’s Library electronic databases were systematically searched for randomized controlled trials (RCTs) investigating the clinical efficacy of vaptans in cirrhosis patients. The results were pooled with a random-effect model.

Results: Eighteen RCTs containing 3,059 cirrhosis patients with ascites and/or hyponatremia were included. Meta-analysis showed that vaptans did not significantly affect the risk of all-cause mortality (RR: 1.02, 95% CI: 0.87 to 1.08, p = 0.83; I² = 2%), consistent with studies with short-term (< 26 weeks) and long-term (≥ 26 weeks) follow-up durations. Additionally, vaptans did not affect the incidence of variceal bleeding (RR: 0.96, p = 0.86), showed a trend of reduced incidence of hepatic encephalopathy (RR: 0.86, p = 0.09), significantly reduced the incidence of spontaneous bacterial peritonitis (RR: 0.75, p = 0.03), but did not significantly affect the risk of hepatorenal syndrome or renal failure (RR: 1.09, p = 0.36). Vaptans did not affect the incidence of adverse events in cirrhosis patients.

Discussion: Treatment with vaptans is not associated with improved survival in cirrhosis patients, although it may reduce the risk of hepatic encephalopathy and spontaneous bacterial peritonitis in these patients. The limitations of the current study include limited number of available studies, small sample sizes of the included studies, variations of baseline patient characteristics, and differences in the dose and duration of vaptans.

The effects of extended nitric oxide release on responses of the human non-pregnant myometrium to endothelin-1 or vasopressin

BACKGROUND

Uterotonic mediators: endothelin-1 (ET-1), arginine vasopressin (AVP), and nitric oxide (NO) play important roles in the regulation of uterine contractility. We hypothesize that NO affects both ET-1 or AVP. Therefore, this study investigated the involvement of extended exogenous NO release in the regulation of responses of the human non-pregnant myometrium to ET-1 and AVP.

METHODS

Specimens were obtained from 10 premenopausal women, undergoing hysterectomy for benign gynecological disorders. Responses of the myometrial strips to ET-1 or AVP in the absence and presence of an exogenous NO donor (diethylenetriamine; DETA/NO; 10-4 mol/L) were recorded under isometric conditions. To inhibit endogenous NO, a competitive inhibitor of NO synthase, L-NG-nitroarginine (L-NNA) was added to the organ bath.

RESULTS

ET-1 enhanced the spontaneous contractile activity of the myometrium more powerfully (p < 0.01) than AVP. Preincubation with exogenous NO weakened ET-1- or AVP-induced increases in this contractile activity (p < 0.05). However, unexpected results were obtained after preincubation with L-NNA and with DETA/NO then added. Both ET-1 and AVP induced augmented contractile effects in almost all concentrations compared with the responses to these peptides alone or after NOS synthase inhibition (both p < 0.01).

CONCLUSIONS

This study demonstrated for the first time that extended incubation with a NO donor influences the uterine muscle response evoked by ET-1 and AVP. Both endogenous and exogenous NO is involved in the control of the uterine responses to ET-1 or AVP of non-pregnant myometrium. Furthermore, both peptides stimulate increased uterine contractility when the local imbalance between the constrictive and relaxing mediators takes place.

Estimated Daily Urine Volume and Solute Excretion from Spot Urine Samples to Guide the Therapy of Hyponatremia in SIADH

Background: In hyponatremia, due to the inappropriate secretion of antidiuretic hormone (SIADH), a high versus low solute intake will affect the urine volume (UV) and, hence, the SNa level. The clinical implication of the fractional solute excretion is presented. Methods: In 35 normal controls and 24 patients with SIADH and urine osmolality higher than serum osmolality, we compared exact solute intake obtained from 24 h urine collection, with the estimated value obtained on a urine morning spot sample by the formula: eGFR (L/min) × Sosm × 1440 × FE.Osm (%) = mmol/24 h. The exact UV was compared with the estimated value given by the formula: eGFR × 1440 × S.Creat/U.Creat (for eGFR the MDRD was used). In 65 patients with chronic SIADH, from which a morning spot urine sample was available, we determined the estimated fluid and solute intake. Results: A good correlation was observed between the measured solute output or urine volume and the estimated values obtained from the controls (r = 0.86) as well as in SIADH (r = 0.91). Conclusion: Patients with low solute intake (FE.Osm <1.4%) and low diuresis (V/eCcr <0.8%) should increase their intake by taking oral urea, for example. Patients with high solute intake (FE.Osm >2.5%) and high diuresis (V/eCcr >1.5%) could usually be treated by mild water restriction (<1.5–21/24 h).

Phosphine-Catalyzed α-Umpolung-Aldol Reaction for the Synthesis of Benzo[ b]azapin-3-ones

A novel phosphine-catalyzed intermolecular cyclization between 2-sulfonamidobenzaldehyes and ynones is reported. This methodology serves as a conduit for the construction of benzo[ b]azepin-3-ones in good to excellent yields under mild conditions. The resulting 2-benzylidene moieties are formed exclusively in the E-configuration. Mechanistically, this unusual annulation occurs through a phosphine-catalyzed α-umpolung addition, followed by an aldol reaction. One of the benzo[ b]azepin-3-one products was converted to the core structure of 3-amino-[ a]benzazepin-2-one-1-alkanoic acids, many of which function as angiotensin-converting enzyme inhibitors.

Hypernatremia induced by low-dose Tolvaptan in a Patient with refractory heart failure: A case report

RATIONALE

Tolvaptan (TLV) is a selective vasopressin type 2 receptor antagonist, which has an active effect on patients with congestive heart failure especially combined with hyponatremia. Increasingly, evidence has demonstrated that low-dose tolvaptan can dramatically relieve patients' dyspnea and the dose would not cause severe electrolyte abnormalities. Even hypernatremia is a major adverse effect of tolvaptan, treatment with tolvaptan shows good security and is well-tolerated. Few cases have reported that patients who developed severe hypernatremia induced by low-dose Tolvaptan.

PATIENT CONCERNS

A 68-year-old man was admitted to our hospital with dyspea and general fatigue. He was diagnosed with acute decompensated heart failure due to ischemic cardiomyopathy. In order to improve fluid retention and relieve his dyspnea, low-dose TLV (7.5 mg qd) was performed. After the 3-day treatment using TLV, we observed that he became delirious and his limbs shook uncontrollably. High serum sodium 173 mmol/L was noted compared to the results of the first examination (137 mmol/L). After intensive rescue, serum sodium was restored to normal (135 mol/L). Later, when the patient refused continuous renal replacement therapy (CRRT), we tried again to use a lower dose of TLV to improve diuretic resistance. Two days later, Serum sodium rose again (162 mmol/L).

DIAGNOSES

During the course of therapy, we did not strictly require the patient to control the fluid intake. No other medication could cause elevation of serum sodium. Therefore, we suspected a high sensitivity to the side effect of TLV.

INTERVENTION

Stop the use of TLV and encourage the patient to drink plenty of water. Gastric tube was inserted orally to increase the intake of fresh water.

OUTCOMES

His serum sodium decreased gradually and his psychiatric symptom recovered. During this period, Overall condition of the patient was stable. After being discharged from the hospital, the patient eventually died of cardiac arrest due to critically ill heart failure.

LESSONS

Hypernatremia is a severe side effect of TLV. For critical patients, TLV should be used at a low dose and electrolyte should be detected in time.

Efficiency of Single Dose of Tolvaptan Treatment During the Triphasic Episode After Surgery for Craniopharyngioma

Inappropriate antidiuretic hormone syndrome (SIADH) may develop after intracranial surgery. SIADH in the pediatric age group is usually encountered in patients with an intracranial mass both before and after surgery. Fluid restriction is the standard therapy in SIADH. However, a resistant, hyponatremic pattern may be encountered in some cases. Vaptans have been recently introduced for treatment of hyponatremia due to SIADH. There is inadequate data concerning tolvaptan treatment in pediatric patients. We present a 13 year-old female with SIADH of triphasic episode who was transferred to our clinic after surgery for craniopharyngioma. Resistant hyponatremia did not resolve despite fluid restriction and hypertonic saline support. The patient responded rapidly to a single dose of tolvaptan, with no adverse effect, which resulted in successful control of her SIADH.