Expression of aquaporin-2 in the collecting duct and responses to tolvaptan

Kakeshita, Kota; Koike, Tomoyuki; Imamura, Teruhiko; Fujioka, Hayato; Yamazaki, Hidenori; Kinugawa, Koichiro

doi:10.1007/s13730-020-00518-1

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…These individuals were afflicted by septic or cardiogenic shock and presented with impaired renal function. Similar to observations with oral tolvaptan, the residual function of the kidney collecting duct might play a pivotal role in determining the responsiveness to tolvaptan therapies [22]. Optimal patient selection and therapeutic strategies for nonresponders to TSP remain the next concerns.…”

Section: Efficacy Analysismentioning

confidence: 81%

Preliminary Report of Intravenous Tolvaptan Sodium Phosphate (Samtas®) Treatment in Decompensated Heart Failure

Nakamura,

Imamura,

Kinugawa

2024

JCM

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Background: Tolvaptan sodium phosphate (Samtas®; Otsuka Pharmaceutical, Tokyo, Japan) is a novel intravenous aquaretic diuretic aimed at individuals experiencing advanced congestion refractory to conventional diuretics and having difficulty with oral intake. Despite its potential, the true efficacy and practicality of this compound within real-world clinical settings remain obscure. Methods: A retrospective analysis of clinical data was conducted, examining trends among consecutive in-hospital patients diagnosed with congestive heart failure who underwent treatment with tolvaptan sodium phosphate at a prominent academic medical center between June 2022 and June 2023. Results: Twenty-one patients were enrolled (median age: 75 years, serum N-terminal pro B-type natriuretic peptide: 8941 pg/mL). Among them, 14 patients (67%) received non-invasive/invasive positive-pressure ventilation, and 17 patients (81%) concurrently received intravenous inotropes. Subsequent to the initiation of tolvaptan sodium phosphate treatment, a significant increase in urine volume was observed on the following day (p = 0.036). Urine osmolality decreased from 356 (318, 443) at baseline to 247 (176, 333) mOsm/kg after 4 h (p = 0.002). No occurrences of hypernatremia were recorded during the therapeutic period. Notably, two patients transitioned from tolvaptan sodium phosphate treatment to continuous hemodiafiltration due to insufficient efficacy. Conclusions: In routine clinical practice, intravenous tolvaptan sodium phosphate exhibits potential efficacy and practicability in the majority of congestive heart failure patients exhibiting refractory congestion, unstable hemodynamics, and challenges with oral intake.

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Section: Efficacy Analysismentioning

confidence: 81%

Preliminary Report of Intravenous Tolvaptan Sodium Phosphate (Samtas®) Treatment in Decompensated Heart Failure

Nakamura,

Imamura,

Kinugawa

2024

JCM

Self Cite

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“…In other words, AQP2 may be a useful marker for estimating tolvaptan responses, notably in CKD patients. In addition, a study was conducted in which urine AQP2 (U-AQP2) was used as an innovative non-invasive marker to predict responses to tolvaptan in humans [ 57 , 58 ]. Urine AQP2 excretion in dogs can still be used as a prognostic tool to differentiate polyuria diseases such as central or NDI, inappropriate arginine vasopressin protein release, and primary polydipsia [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

Comparative quantitation of aquaporin-2 and arginine vasopressin receptor-2 localizations among chronic kidney disease and healthy kidney in dogs

et al. 2021

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Background and Aim: Aquaporin-2 (AQP2) and arginine vasopressin receptor-2 (AVPR2) are proteins that control water homeostasis in principal cells. Chronic kidney disease (CKD) is defined as the impairment and irreversible loss of kidney function and/or structure, which causes water imbalances and polyuria. The study aimed to know the expression of AQPs and AVPR2 in the kidneys of a canine with CKD. Materials and Methods: The kidneys were collected from two dog carcasses from Small Animal Teaching Hospital, Faculty of Veterinary Medicine, Chiang Mai University. The kidney tissue was prepared for immunohistochemistry and investigated the expression and localization of tissue's AQP2 and AVPR2. For statistical analysis, the Mann–Whitney U-test was applied to the data. Results: By immunohistochemistry, AQP2 was expressed strongly in the basolateral and apical membranes of the principal cells, whereas AVPR2 was localized in the principal cell's basolateral membrane in both renal cortex and renal medulla. In the normal kidney, the semi-quantitative immunohistochemistry for the percentage of protein expression of AQP2 and AVPR2 was 5.062±0.4587 and 4.306±0.7695, respectively. In contrast, protein expression of AQP2 and AVPR2 in CKD was found to be 1.218±0.1719 and 0.8536±0.1396, respectively. The data shows that the percentage of AQP2 and AVPR2 expression was decreased, corresponding to a 4-fold and 5-fold in CKD (p<0.001). Conclusion: Our findings revealed that CKD was a marked decrease in AQP2 and AVPR2 expression. The central role of specific AQP2 and AVPR2 in regulating water homeostasis will provide correlations in case of CKD with polyuria.

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Prognostic impact of urine cyclic AMP levels in patients with chronic kidney disease

et al. 2022

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Expression of aquaporin-2 in the collecting duct and responses to tolvaptan

Cited by 5 publications

References 7 publications

Preliminary Report of Intravenous Tolvaptan Sodium Phosphate (Samtas®) Treatment in Decompensated Heart Failure

Preliminary Report of Intravenous Tolvaptan Sodium Phosphate (Samtas®) Treatment in Decompensated Heart Failure

Comparative quantitation of aquaporin-2 and arginine vasopressin receptor-2 localizations among chronic kidney disease and healthy kidney in dogs

Prognostic impact of urine cyclic AMP levels in patients with chronic kidney disease

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