V2 Receptor Antagonist Research Articles

Effect of vasopressin V2-receptor antagonist tolvaptan on syndrome of inappropriate antidiuresis (SIAD) after transsphenoidal pituitary surgery: recovery of measured osmolality

BackgroundDelayed hyponatremia after pituitary surgery can be treated with the V2-receptor antagonist, oral tolvaptan. We investigated the pharmacological effect of oral tolvaptan against SIAD in patients with hyponatremia after pituitary surgery. MethodsThirty-nine patients with pituitary adenoma treated by endoscopic transsphenoidal surgery developed SIAD according to the major guidelines, and 7 patients (17.9%) were treated with tolvaptan. Tolvaptan was administrated orally half a tablet (3.75 mg) once in the first two cases, and half a tablet twice in the other five cases. Serum osmolality, urinary osmolality, urinary sodium concentration, urinary volume, and serum sodium and potassium concentration were evaluated before administration, and after the last oral administration of tolvaptan. Serum osmolality and urine osmolality were physically measured. ResultsSerum sodium concentration was significantly increased from 132.1 ± 4.0 to 143.0 ± 2.9 mmol/L (mean ± standard deviation, n = 7, P < 0.001). Serum osmolality was significantly increased from 266.3 ± 7.7 to 289.6 ± 6.7 mOsm/kg (n = 7, P < 0.001). Urine osmolality was significantly reduced from 607.1 ± 240.4 to 262.7 ± 115.6 mOsm/kg (n = 7, P = 0.01). Urinary sodium concentration was significantly decreased from 121.3 ± 48.4 to 36.9 ± 35.0 mOsm/kg (n = 7, P = 0.001). Urine output (24-hour including the first administration) was significantly increased from 1384.2 ± 550.7 to 3291.3 ± 1710.9 mL/day (n = 6, P = 0.026). ConclusionsOral tolvaptan administration corrects SIAD after pituitary surgery. Hyponatremia after pituitary surgery was confirmed to be due to SIAD.

Outcomes from the Northeast England cohort of autosomal dominant polycystic kidney disease (ADPKD) patients on tolvaptan.

Autosomal dominant polycystic kidney disease (ADPKD) is a cause of end-stage kidney disease (ESKD). The vasopressin V2-receptor antagonist tolvaptan has been shown within randomized clinical trials to slow down decline of kidney function in patients with ADPKD at risk of rapid progression. We performed a retrospective review of a Northeast England cohort of adult ADPKD patients who had been established on tolvaptan therapy to determine its efficacy in a real-world clinic setting. Other inclusion criteria involved a pre-treatment decline in greater than 2.5 ml/min/1.73m2/year based on readings for a 3 year period, and ability to tolerate and maintain tolvaptan treatment for at least 12 months. We calculated based on eGFR slopes, predicted time to reach ESKD with and without tolvaptan therapy. The cohort of patients included 21 from the Northeast of England. The mean rate of eGFR decline prior to treatment was -6.02 ml/min/1.73m2/year for the cohort. Following tolvaptan treatment, the average decline in eGFR was reduced to -2.47 ml/min/1.73m2/year, gaining a mean 8 years and 4 months delay to reach ESKD. The majority of patients (n=19) received and tolerated full dose tolvaptan (90 mg/30 mg). The real-life use of tolvaptan gave a dramatic improvement in eGFR slopes, much more than previously reported in clinical studies. These effects may be in part due to careful patient identification, selection and inclusion of patients who were able to tolerate tolvaptan therapy, excellent compliance with medication and a "tolvaptan clinic" effect where great personal care was given to these patients.

Clinical Utility and Tolerability of Tolvaptan in the Treatment of Autosomal Dominant Polycystic Kidney Disease (ADPKD).

Autosomal dominant polycystic kidney disease, also known as ADPKD, is the most common hereditary kidney disease, affecting different age groups. ADPKD can eventually lead to end-stage renal disease. The etiology of ADPKD is genetic, resulting in the formation of cysts containing fluids on the kidneys. Patients with ADPKD present a range of symptoms following a decline in kidney function. Pain, stones, proteinuria and osteoporosis are few of the many symptoms, resulting from decreased kidney function. Tolvaptan, a selective V2 receptor antagonist, is the etiological treatment used for ADPKD. In this paper, we conducted a systematic review of the literature between 2011 and 2021 to gather data regarding the tolerability and efficacy of tolvaptan use in ADPKD. A total of 22 trials were reviewed. Tolvaptan efficacy in the trials was measured using changes in eGFR or changes in total kidney volume. Results showed that tolvaptan use in ADPKD was associated with a slower decline in kidney function and a decrease in total kidney volume. Side effects of this drug include polyuria, nocturia and polydipsia along with hepatotoxicity. The two biggest trials, TEMPO and REPRISE, change in eGFR from pre-treatment baseline to post-treatment was 1.3 mL/min/1.73 for REPRISE and 1 mL/min/1.73 for TEMPO 3:4. A mean decrease of 49% in total kidney volume from baseline to post-treatment was found in the TEMPO 3:4 study.

In vitro and in vivo pharmacological profile of OPC-61815, a water-soluble phosphate ester pro-drug of tolvaptan

Tolvaptan is an orally active vasopressin V2 receptor antagonist and used for the treatment of volume overload in some disease as an aquaretic. Tolvaptan sodium phosphate (OPC-61815) is a pro-drug of tolvaptan that was designed to improve water solubility and enable intravenous use. The conversion of OPC-61815 to tolvaptan was evaluated for in vitro and in vivo pharmacokinetic studies. The pharmacodynamics of OPC-61815 were evaluated for in vitro receptor binding affinity, in vivo aquaretic and anti-edematous action. The solubility of OPC-61815 in water at 25 °C was 72.4 mg/mL and more than 100,000 times the solubility of tolvaptan. OPC-61815 was hydrolyzed to tolvaptan by human tissue S9 fractions and main enzyme of hydrolysis was alkaline phosphatase. After intravenous administration of OPC-61815 to rats and dogs, tolvaptan was detected in plasma within 5 min and the bioavailability of tolvaptan was 57.7% and 50.9%, respectively. Binding affinity of OPC-61815 for the human V2 receptor was 1/14 weaker than that of tolvaptan. OPC-61815 exerted dose-dependent aquaretic action in rats and dogs and a corresponding anti-edematous action in rat edema models. These results suggest that OPC-61815, a water-soluble phosphate ester pro-drug of tolvaptan, is an effective aquaretic by converting to tolvaptan after intravenous administration.

Regional variation in tolvaptan prescribing across England: national data and retrospective evaluation from an expert centre.

Tolvaptan, a vasopressin V2 receptor antagonist, was approved in 2015 by the UK National Institute for Health and Care Excellence for use in patients with autosomal dominant polycystic kidney disease (ADPKD) and rapid disease progression. Simultaneous guidance was issued by the UK Kidney Association (UKKA) to facilitate national implementation. Data on tolvaptan prescribing in England was obtained through the National Health Service (NHS) Digital, a national survey of all 77 adult kidney units, and the implementation of UKKA guidance was evaluated at an expert PKD centre. A regional variation of up to 4-fold for tolvaptan prescribing in England was found. Despite most kidney units following UKKA guidance, centre-based estimates of eligible or treated patient numbers were highly variable. Retrospective evaluation at an expert PKD centre revealed that in a cohort demonstrating rapid estimated glomerular filtration rate (eGFR) decline, 14% would not be eligible for tolvaptan by Mayo imaging classification and more than half (57%) would not be eligible by Predicting Renal Outcome in Polycystic Kidney Disease score. The 3-year discontinuation rate was higher than expected (56%), the majority (70%) due to aquaretic symptoms. In patients taking tolvaptan for at least 2years, 81% showed a reduction in the rate of eGFR decline compared with baseline, with earlier disease associated with positive treatment response. Real-world data have revealed a much higher regional variation in tolvaptan prescribing for ADPKD in England than expected. We propose further investigation into the factors responsible for this variation.

Effect of Tolvaptan in Patients with Chronic Kidney Disease Stage G5, and Impact of Concomitant Use of Thiazide Diuretics: A Retrospective Cohort Study.

The diuretic effect of tolvaptan, a vasopressin V2 receptor antagonist, in patients with severe renal dysfunction remains poorly characterized. Thiazide diuretics reduce urinary volume (UV) in patients with nephrogenic diabetes insipidus, which lacks V2 receptor function. This retrospective study investigated the acute urinary effects of tolvaptan in patients with stage G5 chronic kidney disease and congestive heart failure (CHF), and the impact of thiazide diuretics on the urinary effects of tolvaptan. UVs 24h before and after tolvaptan administration and 30-day dialysis initiation rate were compared between patients with and without thiazide diuretic administration. Thiazide diuretics were used in 26 of the 106 recruited patients (age 73.4±13.0 years; estimated glomerular filtration rate 8.07±3.13 mL/min/1.73 m2). The pre- and post-tolvaptan 24-h UVs were significantly higher in patients not administered thiazide diuretics (1043.4±645.6 vs. 1422.2±774.0 mL/day; p<0.001) than in those administered thiazide diuretics (1177.3±686.5 vs. 1173.1±629.1 mL/day; p=0.93). In a multivariate regression model, thiazide diuretic use was significantly associated with decreased 24-h UV (β coefficient -486.7, 95% confidence interval [CI] -674.5 to -298.8); increased urine osmolality (β coefficient 37.7, 95% CI 17.1-58.4); increased body weight (β coefficient 0.62, 95% CI 0.31-0.92); and increased 30-day dialysis initiation rate (odds ratio 3.40, 95% CI 1.18-9.82) after tolvaptan administration. Tolvaptan exhibited significant diuretic effects in patients with CHF, including those with severe renal dysfunction, which were diminished with concomitant thiazide diuretic use.

Drugs in Clinical Development to Treat Autosomal Dominant Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst formation that ultimately leads to kidney failure in most patients. Approximately 10% of patients who receive kidney replacement therapy suffer from ADPKD. To date, a vasopressin V2 receptor antagonist (V2RA) is the only drug that has been proven to attenuate disease progression. However, aquaresis-related adverse events limit its widespread use. Data on the renoprotective effects of somatostatin analogues differ largely between studies and medications. This review discusses new drugs that are investigated in clinical trials to treat ADPKD, such as cystic fibrosis transmembrane conductance regulator (CFTR) modulators and micro RNA inhibitors, and drugs already marketed for other indications that are being investigated for off-label use in ADPKD, such as metformin. In addition, potential methods to improve the tolerability of V2RAs are discussed, as well as methods to select patients with (likely) rapid disease progression and issues regarding the translation of preclinical data into clinical practice. Since ADPKD is a complex disease with a high degree of interindividual heterogeneity, and the mechanisms involved in cyst growth also have important functions in various physiological processes, it may prove difficult to develop drugs that target cyst growth without causing major adverse events. This is especially important since long-standing treatment is necessary in this chronic disease. This review therefore also discusses approaches to targeted therapy to minimize systemic side effects. Hopefully, these developments will advance the treatment of ADPKD.

Management of Decongestion in Acute Heart Failure: Time for a New Approach?

As the primary cause of hospitalization in acute heart failure (AHF) patients, congestion was responsible for a higher risk of mortality, rehospitalization, and renal dysfunction in AHF patients. Although loop diuretic was routinely used as the mainstay of AHF therapy, it is still ineffective to obtain the euvolemic state in most hospitalized AHF patients. Therefore, a higher loop diuretic dose was often required to increase the decongestion effect. However, consequently, it can cause several detrimental complications, including renal dysfunction, neurohormonal activation, hyponatremia, hypokalaemia, and reduced blood pressure, which eventually result in poor prognosis. Hence, the new approach may be proposed to optimize decongestion in acute phase, including the use of arginine vasopressin V2 receptor antagonist – Tolvaptan. As an additive therapy to loop diuretic in AHF patients, it can be considered due to its several beneficial effects, including greater decongestion effect, lowered worsening renal function incidence, counteract neurohormonal activation, neutralized hyponatraemic state, no alteration of potassium metabolism, stabilize the blood pressure, and reduced requirement of a higher dose of loop diuretic to achieve an equal or even greater decongestion effect compared to a high dose of loop diuretic alone. Tolvaptan provided favourable outcomes in several specific populations and was considered safe with several mild adverse effects. Several guidelines across countries have approved the use of Tolvaptan in AHF patients with or without hyponatremia. The initial dose of Tolvaptan was 7.5 to 15 mg and can be titrated up to 30 mg. However, further studies were still required to determine the timing dose and optimal dose of Tolvaptan in general and elderly populations with AHF, respectively.

Clinical Implication of Tolvaptan in Patients with Autosomal Dominant Polycystic Kidney Disease

Tolvaptan, a non-peptide arginine vasopressin V2 receptor antagonist, is a newly developed drug to reduce kidney volume and preserve kidney function in autosomal dominant polycystic kidney disease (ADPKD) patients. We aimed to evaluate the descriptive characteristics of patients according to the use of tolvaptan. Also, we tried to find the efficacy of tolvaptan on kidney volume and kidney function. We included patients with ADPKD who visited a tertiary hospital in South Korea during Sep. 2018 and Apr. 2022. The data was acquired from the Electric Medical Records system. A total of 64 patients were included in the study, and there were 33 (51.6%) patients taking tolvaptan during follow-up periods. During 17.8 ± 13.1 months of follow-up periods, estimated glomerular filtration rate (eGFR) changes were 89.4% compared to the baseline eGFR. Although the latest eGFR was lower in patients with tolvaptan (55.9 ± 24.7 mL/min/1.73 m2) than without tolvaptan (68.4 ± 35.1 mL/min/1.73 m2), there was no statistical significance (p = 0.108). We found that the mean change of height-adjusted total kidney volume (HtTKV) was -2.7% based on the baseline HtTKV in patients taking tolvaptan for more than 1-year. Although there was no statistical significance, the mean change of HtTKV was the highest in patients with 1E of Mayo classification (-4.3%). To anticipate the solid data on the efficacy of tolvaptan in the Asian population, more aggressive efforts are needed to search for suitable patients accompanied by appropriate monitoring over a more extended period. Keywords: Chronic kidney disease, Polycystic kidney, autosomal dominant, Tolvaptan

Evidence for a Prehypertensive Water Dysregulation Affecting the Development of Hypertension: Results of Very Early Treatment of Vasopressin V1 and V2 Antagonism in Spontaneously Hypertensive Rats.

In addition to long-term regulation of blood pressure (BP), in the kidney resides the initial trigger for hypertension development due to an altered capacity to excrete sodium and water. Betaine is one of the major organic osmolytes, and its betaine/gamma-aminobutyric acid transporter (BGT-1) expression in the renal medulla relates to interstitial tonicity and urinary osmolality and volume. This study investigated altered water and sodium balance as well as changes in antidiuretic hormone (ADH) activity in female spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats from their 3–5 weeks of age (prehypertensive phase) to SHR’s 28–30 weeks of age (established hypertension-organ damage). Young prehypertensive SHRs showed a reduced daily urine output, an elevated urine osmolarity, and higher immunostaining of tubule BGT-1, alpha-1-Na-K ATPase in the outer medulla vs. age-matched WKY. ADH circulating levels were not different between young prehypertensive SHR and WKY, but the urine aquaporin2 (AQP2)/creatinine ratio and labeling of AQP2 in the collecting duct were increased. At 28–30 weeks, hypertensive SHR with moderate renal failure did not show any difference in urinary osmolarity, urine AQP2/creatinine ratio, tubule BGT-1, and alpha-1-Na-K ATPase as compared with WKY. These results suggest an increased sensitivity to ADH in prehypertensive female SHR. On this basis, a second series of experiments were set to study the role of ADH V1 and V2 receptors in the development of hypertension, and a group of female prehypertensive SHRs were treated from the 25th to 49th day of age with either V1 (OPC21268) or V2 (OPC 41061) receptor antagonists to evaluate the BP time course. OPC 41061-treated SHRs had a delayed development of hypertension for 5 weeks without effect in OPC 21268-treated SHRs. In prehypertensive female SHR, an increased renal ADH sensitivity is crucial for the development of hypertension by favoring a positive water balance. Early treatment with selective V2 antagonism delays future hypertension development in young SHRs.

The V2 receptor antagonist tolvaptan counteracts proliferation and invasivity in human cancer cells

PurposeHyponatremia, the most frequent electrolyte alteration in clinical practice, has been associated with a worse prognosis in cancer patients. On the other hand, a better outcome has been related to serum sodium normalization. In vitro studies have shown that low extracellular sodium promotes cancer cells proliferation and invasiveness. Tolvaptan, a selective vasopressin receptor type 2 (V2) antagonist, has been effectively used in the last decade for the treatment of hyponatremia secondary to the Syndrome of Inappropriate Antidiuresis. A few in vitro data suggested a direct role of tolvaptan in counteracting cancer progression, so far. The aim of this study was to evaluate the effect and the mechanism of action of tolvaptan in cell lines from different tumours [i.e. colon cancer (HCT-8), hepatocarcinoma (HepG2), neuroblastoma (SK-N-AS)].Methods and resultsFirst, we showed that these cell lines express the V2 receptor. Tolvaptan significantly reduced cell proliferation with an IC50 in the micromolar range. Accordingly, reduced levels of cAMP, of the catalytic α subunit of PKA, and a reduced pAKT/AKT ratio were observed. Tolvaptan effectively inhibited cell cycle progression, whereas it induced apoptotis. Furthermore, it reduced cell invasiveness. In particular, anchorage-independent growth and the activity of collagenases type IV were blunted in the three cell lines. Accordingly, tolvaptan counteracted the RhoA/ROCK1–2 pathway, which has a pivotal role in regulating cell movement.ConclusionsOverall, these findings indicate that tolvaptan effectively inhibits tumour progression in vitro. Further studies should clarify whether the V2 receptor might be considered a possible target in anti-cancer strategies in the future.

Transcriptomic and metabolic profiling of Tolvaptan treated Autosomal dominant polycystic kidney disease (ADPKD) patient

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is the most common and life‐threatening genetic kidney disease that characterized by the aberrant renal tubule epithelial cells proliferation leads to the formation of multiple fluid‐filled cysts, and most of the ADPKD patient will leads to kidney failure by age of 50. Currently, dialysis or a transplant are the only treatments for end‐stage ADPKD patients. Tolvaptan is a is a selective vasopressin V2‐receptor antagonist which was used to treat hyponatremia in heart failure but was approved by FDA for ADPKD treatment in 2018. However, there are limitations for ADPKD patients to receive Tolvaptan treatment and significant side effects severely affect patient’s life quality. In our study, a 34‐year‐old man was diagnosed with familial ADPKD. He had cysts in kidney (Mayo class 1c) and liver and showed no symptoms other than hypertension. His baseline eGFR was 76.98 ml/min/1.732mg/dL but declined to 57.02 ml/min/1.732mg/dL two years after his first diagnosis, and there was an increase in number and size of the cysts due to the rapidly progressive ADPKD. Tolvaptan was started with the 45‐0‐15 dose and the patient was well‐tolerated. After 60 days of treatment, the renal function dramatic improved (73.02 ml/min/1.732mg/dL). With the titrate to 60‐0‐30 dose of tolvaptan, his eGFR maintains above than 60 ml/min/1.732mg/dL more than 3 months until present.MethodInformation of transcriptome and metabolome has significantly contributed to identifying potential therapeutic targets for the management of diseases. In our study, we collect his blood and urine before Tolvaptan treatment and 2 and 3 months after Tolvaptan treatment for transcriptomic and metabolic profiling. Total RNA was extracted using Trizol® Reagent (Invitrogen, USA) according to the manual. cDNA libraries were prepared by SureSelect XT HS2 mRNA Library Preparation kit (Agilent, USA) and sequenced on Nextseq. Differential expression analysis was performed using StringTie and DEseq2 with genome bias detection/correction using Welgene Biotech's in‐house pipeline. Genes with p value &lt; 0.05 and &gt; 2.0‐fold changes were considered significantly differentially expressed, and functional enrichment assay in differentially expressed genes of each experiment design was performed using clusterProfiler v3.6.ResultsOur data indicates that tight junction proteins (Log2 ratio: CRB3, 11.01; CLDN10, 10.09; MAPK10, 7.34), cytoskeleton regulating proteins (Log2 ratio: FGF17, 9.47; MYH14, 7.04) which also genes involved in the regulation of calcium and MAPK signaling and following focal adhesion proteins were significantly (p&lt;0.05) preserved after 3 months Tolvaptan treatment. Furthermore, Hypoxanthine, Creatine, L‐a‐aminobutyric acid and Trimethylamine N‐oxide were significantly decreased in our metabolomics data analysis which is also indicates the inhibition of paracellular transportation in kidney epithelial/endothelial cells.ConclusionOur data indicates a potential molecular mechanism of Tolvaptan treatment in regulating the integrity of tight junction and kidney cells, and provides novel therapeutic targets in in ADPKD.

Tolvaptan induces body fluid loss and subsequent water conservation in normal rats

We have recently reported that the urea osmolyte-associated water conservation system is activated in fluid loss models such as high salt-induced natriuresis, renal injury-induced impaired renal concentrating ability, or skin barrier dysfunction-induced transepidermal water loss. The system consists of the interaction of multiple organs including renal urea recycling, hepato-muscular ureagenesis, and suppression of cardiovascular energy expenditure. Here, we determined the effect of pharmacological fluid loss induced by tolvaptan, a selective vasopressin V2 receptor antagonist, on water conservation. We evaluated the water conservation system in rats that consumed a control diet or a diet containing 0.1% tolvaptan. Tolvaptan increased urine volume on day 1, but this renal water loss then gradually decreased. Body water and osmolyte content were decreased by tolvaptan on day 1 but had normalized by day 7. Tolvaptan induced fluid loss on day 1, and the following restoration of body fluid on day 7 was associated with an increase in urea transporter A1-associated renal urea recycling. Tolvaptan did not affect hepato-muscular ureagenesis on day 1 and day 7, or cardiovascular energy expenditure during treatment. Thus, tolvaptan-induced fluid loss leads to activation of the water conservation system via renal urea recycling.

Long Residence Time at the Vasopressin V2 Receptor Translates into Superior Inhibitory Effects in Ex Vivo and In Vivo Models of Autosomal Dominant Polycystic Kidney Disease.

Prevailing strategies directing early-phase drug discovery heavily rely on equilibrium-based metrics such as affinity, which overlooks the kinetic process of a drug molecule interacting with its target. Herein, we developed a number of vasopressin V2 receptor (V2R) antagonists with divergent binding affinities and kinetics for autosomal dominant polycystic kidney disease (ADPKD). Surprisingly, the residence time of the V2R antagonists, but not their affinity, was correlated with the efficacy in both ex vivo and in vivo models of ADPKD. We envision that the kinetics-directed drug candidate selection and development may have general applicability for ADPKD and other therapeutic areas as well.

Effects of Hydrochlorothiazide and Metformin on Aquaresis and Nephroprotection by a Vasopressin V2 Receptor Antagonist in ADPKD: A Randomized Crossover Trial.

The vasopressin V2 receptor antagonist tolvaptan is the only drug that has been proven to be nephroprotective in autosomal dominant polycystic kidney disease (ADPKD). Tolvaptan also causes polyuria, limiting tolerability. We hypothesized that cotreatment with hydrochlorothiazide or metformin may ameliorate this side effect. We performed a clinical study and an animal study. In a randomized, controlled, double-blind, crossover trial, we included 13 tolvaptan-treated patients with ADPKD. Patients were treated for three 2-week periods with hydrochlorothiazide, metformin, or placebo in random order. Primary outcome was change in 24-hour urine volume. We also measured GFR and a range of metabolic and kidney injury markers. Patients (age 45±8 years, 54% women, measured GFR of 55±11 ml/min per 1.73 m2) had a baseline urine volume on tolvaptan of 6.9±1.4 L/24 h. Urine volume decreased to 5.1 L/24 h (P<0.001) with hydrochlorothiazide and to 5.4 L/24 h (P<0.001) on metformin. During hydrochlorothiazide treatment, plasma copeptin (surrogate for vasopressin) decreased, quality of life improved, and several markers of kidney damage and glucose metabolism improved. Metformin did not induce changes in these markers or in quality of life. Given these results, the effect of adding hydrochlorothiazide to tolvaptan was investigated on long-term kidney outcome in an animal experiment. Water intake in tolvaptan-hydrochlorothiazide cotreated mice was 35% lower than in mice treated with tolvaptan only. Combination treatment was superior to "no treatment" on markers of disease progression (kidney weight, P=0.003 and cystic index, P=0.04) and superior or equal to tolvaptan alone. Both metformin and hydrochlorothiazide reduced tolvaptan-caused polyuria in a short-term study. Hydrochlorothiazide also reduced polyuria in a long-term animal model without negatively affecting nephroprotection. This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_03_21_CJN11260821.mp3.

Prediktor Respons Tolvaptan Sebagai Strategi Optimalisasi Terapi pada Pasien Gagal Jantung: Kajian Naratif

Heart failure (HF) is an end-stage condition of all heart disease and is associated with significant mortality, morbidity, and health expenses. Tolvaptan, a V2 receptor antagonist, is being used in many countries as an adjunct to the diuretic therapy of HF. Although it has been proven effective and safe, some patients do not respond well to the medication. Since there are indications that a specific population can achieve this therapy’s optimal effect, it is essential to identify responders and predictors to develop individual treatment plans. Therefore, this study provides an overview of the effect of tolvaptan and predictors of response that can be used as a strategy in optimizing the treatment of HF. The article searching process was conducted through PubMed, Google Scholar, and Scopus, including predictors, heart failure, and tolvaptan. The predictors identified in the study were urine osmolality, U-AQP2/PAVP, age, serum creatinine, BUN, BUN/Cr, UUN/BUN, UNa/UCr, BNP, AVP/PAC, CKD, HFpEF, and echocardiographic parameters. The variation in results is caused by differences in response definition, patient characteristics, and the types of variables analyzed. Implementing some of these predictors in countries with inadequate hospital facilities and health insurance coverage is complicated. Therefore, the use of response predictors, at any rate, is expected to assist health professionals in considering the risks and benefits of HF therapy.

Potential effect of tolvaptan on polycystic liver disease for patients with ADPKD meeting the Japanese criteria of tolvaptan use.

Polycystic liver disease (PLD) is a common extrarenal complication of autosomal dominant polycystic kidney disease (ADPKD), which causes compression-related syndrome and ultimately leads to liver dysfunction. Tolvaptan, a V2 receptor antagonist, is widely used to protect kidney function in ADPKD but its effect on PLD remains unknown. An observational cohort study was conducted to evaluate tolvaptan's effect on patients with PLD due to ADPKD. After screening 902 patients, we found the 107 ADPKD patients with PLD who met the criteria of tolvaptan use in Japan. Among them, tolvaptan was prescribed for 62 patients (tolvaptan group), while the other was defined as the non-tolvaptan group. Compared with the non-tolvaptan group, the tolvaptan group had larger height-adjusted total kidney volume (median 994(range 450-4152) mL/m, 513 (405-1928) mL/m, p = 0.01), lower albumin level (mean 3.9±SD 0.4 g/dL, 4.3±0.4g/dL, p<0.01), and higher serum creatinine level (1.2±0.4 mg/dL, 0.9±0.2 mg/dL, p<0.01). Although the median change in annual growth rate of total liver volume (TLV) was not statistically different between the tolvaptan group (-0.8 (-15.9, 16.7) %/year) and the non-tolvaptan group (1.7 (-15.6-18.7) %/year)(p = 0.52), 20 (43.5%) patients in the tolvaptan group experienced a decrease in the growth rate of TLV (responders). A multivariable logistic regression model adjusting for related variables showed that older age (odds ratio 1.15 [95% CI 1.01-1.32]) and a higher growth rate of TLV in the non-tolvaptan period (odds 1.45 95% CI 1.10-1.90) were significantly associated with responders. In conclusion, the change in annual growth rate of TLV in ADPKD patients taking tolvaptan was not statistically different compared with that in ADPKD patients without taking tolvaptan. However, tolvaptan may have the potential to suppress the growth rate of TLV in some PLD patients due to ADPKD, especially in older patients or those that are rapid progressors of PLD. Several limitations were included in this study, therefore well-designed prospective studies were required to confirm the effect of tolvaptan on PLD.

Initial decline in eGFR to predict tolvaptan response in autosomal-dominant polycystic kidney disease.

Tolvaptan, a vasopressin V2 receptor antagonist, is used to treat autosomal-dominant polycystic kidney disease (ADPKD). Although tolvaptan curbs disease progression, a few reports have examined factors related to treatment response. The estimated glomerular filtration rate (eGFR) decreases soon after tolvaptan is initiated. We investigated whether initial eGFR decline affects renal prognosis of patients. This was a single-center, retrospective observational cohort study. Eighty-three patients with ADPKD who initiated tolvaptan were selected. We analyzed the relationship of the initial eGFR change with clinical parameters and analyzed the annual eGFR change in terms of renal prognostic value using univariable and multivariable linear regression analyses. The initial eGFR change was -4.6 ± 8.0%/month. The initial eGFR change correlated significantly with the annual eGFR change in multivariable analysis, suggesting that the larger decline in the initial eGFR change, the better the renal prognosis. Furthermore, the change in fractional excretion (FE) of free water (FEH2O) correlated positively with initial eGFR change. FEH2O and urea nitrogen FE (FEUN) increased significantly; however, sodium FE (FENa) level remained unchanged. In approximately half of the patients, FENa unexpectedly decreased. The initial eGFR decline might be caused by suppressing glomerular hyperfiltration, due to the pharmacological effect of tolvaptan, and/or by reducing renal plasma flow, due to potential volume depletion. The initial eGFR change reflects the tolvaptan effect, can be easily evaluated in clinical practice, and may be useful as one of the clinical indicator for predicting renal prognosis in patients under tolvaptan.

Tolvaptan Reduces Extracellular Fluid per Amount of Body Fluid Reduction Less Markedly than Conventional Diuretics.

Objective Tolvaptan, a vasopressin V2 receptor antagonist, is a water diuretic, removing electrolyte-free water from the kidneys and affecting the water balance between the intracellular and extracellular fluid. We previously reported that tolvaptan efficiently reduced the intracellular fluid volume, suggesting its utility for treating cellular edema. Furthermore, tolvaptan is known for its low incidence of worsening the renal function, with conventional diuretics use associated with worsening of the renal function Methods In this retrospective observational study, five chronic kidney disease (CKD) patients with fluid retention were assessed by the bioelectrical impedance (BIA) method twice (before and after tolvaptan therapy). Tolvaptan was used with conventional diuretics. The post/pre ratio of extracellular water (ECW)/total body water (TBW) in the tolvaptan group was compared with that in 18 CKD patients undergoing body fluid reduction with conventional diuretics alone (conventional diuretics groups), taking the reduced amount of body fluid into consideration. Results Removing body fluid, either by tolvaptan or by conventional diuretics alone, decreased the ECW/TBW ratio. Of note, the reduction in extracellular fluid was milder in the tolvaptan group than in the conventional diuretics group. Conclusion Tolvaptan reduces the extracellular fluid per amount of body fluid reduction less markedly than conventional diuretics.

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 (EH2O), 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.