Sodium glucose cotransporter 2 inhibitors in the management of heart failure: Veni, Vidi, and Vici.

Heart failure (HF) is a chronic disease associated with high morbidity and mortality rates. Renin-angiotensin-aldosterone system blockers (including angiotensin receptor/neprilysin inhibitors), beta-blockers, and mineralocorticoid receptor blockers remain the mainstay of pharmacotherapy for HF with reduced ejection fraction (HFrEF). However, despite the use of guideline-directed medical therapy, the mortality from HFrEF remains high. HF with preserved ejection fraction (HFpEF) comprises approximately half of the total incident HF cases; however, unlike HFrEF, there are no proven therapies for this condition. Sodium glucose cotransporter-2 inhibitors (SGLT-2is) represent a new class of pharmacological agents approved for diabetes mellitus (DM) that inhibit SGLT-2 receptors in the kidney. A serendipitous finding from seminal trials of SGLT-2is in DM was the significant improvement in renal and cardiovascular (CV) outcomes. More importantly, the improvement in HF hospitalization (HHF) in the CV outcomes trials of SGLT-2is was striking. Multiple mechanisms have been proposed for the pleiotropic effects of SGLT-2is beyond their glycemic control. However, as patients with HF were not included in any of these trials, it can be considered as a primary intervention. Subsequently, two landmark studies of SGLT-2is in patients with HFrEF, namely, an empagliflozin outcome trial in patients with chronic HF and a reduced ejection fraction (EMPEROR-Reduced) and dapagliflozin and prevention of adverse outcomes in HF (DAPA-HF), demonstrated significant improvement in HHF and CV mortality regardless of the presence of DM. These impressive results pitchforked these drugs as class I indications in patients with HFrEF across major guidelines. Thereafter, empagliflozin outcome trial in patients with chronic HF with preserved ejection fraction (EMPEROR-Preserved) and dapagliflozin evaluation to improve the lives of patients with preserved ejection fraction HF (DELIVER) trials successively confirmed that SGLT-2is also benefit patients with HFpEF with or without DM. These results represent a watershed as they constitute the first clinically meaningful therapy for HFpEF in the past three decades of evolution of HF management. Emerging positive data for the use of SGLT-2is in acute HF and post-myocardial infarction scenarios have strengthened the pivotal role of these agents in the realm of HF. In a short span of time, these classes of drugs have captivated the entire scenario of HF.

Venous Excess Ultrasound Score Is Associated with Worsening Renal Function and Reduced Natriuretic Response in Patients with Acute Heart Failure.

Background: The venous excess ultrasound score (VExUS) is used to objectify systemic venous congestion. The aim of the paper was to determine the association between VExUS grades and worsening renal function (WRF), reduced natriuretic response, diuretics resistance, and mortality in patients with acute heart failure (AHF). Methods: One hundred patients were included, and Doppler ultrasound of hepatic, portal, and renal veins was performed. Severity of congestion was graded using the VExUS score (grade 0, 1, 2, or 3). Sodium concentration in a spot urine sample was assessed in 2 h after the first loop diuretic administration and was adjusted for the prescribed dose of furosemide (31 mmol/40 mg). Diuretics resistance was defined as the need to double the starting dose of intravenous furosemide in 6 h. Results: Patients with VExUS grade 3 showed a higher incidence of WRF (OR: 11.17; 95% CI: 3.86-32.29; p < 0.001) and a decreased natriuretic response: a spot urine sodium content of <50 mmol/L (OR: 21.53; 95% CI: 5.32-87.06; p < 0.001) and an adjusted spot urine sodium content of <31 mmol/40 mg (OR: 9.05; 95% CI: 3.15-25.96; p < 0.001). The risk of diuretic resistance (OR: 15.31; 95% CI: 5.05-46.43; p < 0.001), as well as the need for inotropic and/or vasopressor support (OR: 11.82; 95% CI: 3.59-38.92; p < 0.001), was higher in patients with severe congestion. The hospital mortality rate increased in patients with VExUS grade 3 compared to in patients with other grades (OR: 26.4; 95% CI: 5.29-131.55; p < 0.001). Conclusions: Patients with AHF and VExUS grade 3 showed a higher risk of developing WRF, a decreased diuretic and natriuretic response, a need for inotropic and/or vasopressor support, and a poor prognosis during their hospital stay.

Safety and Efficacy of Dapagliflozin in Recurrent Ascites: A Pilot Study.

BACKGROUND: In cirrhosis, activation of renin-angiotensin-aldosterone system leads to sodium and water retention causing ascites. Dapagliflozin, a sodium glucose linked transporter-2 inhibitor, induces natriuresis in patients with heart failure. A similar natriuretic effect may improve ascites in patients with cirrhosis. In this pilot study, we evaluated the safety and efficacy of dapagliflozin in patients with cirrhosis and recurrent ascites. METHODS: Forty patients with recurrent ascites and cirrhosis were randomized to 1:1 in a double blinded fashion to receive either dapagliflozin (10 mg/day) with standard medical therapy (Group A) or placebo with standard medical therapy (Group B). The primary outcome was control of ascites at 6 months. Secondary outcomes were urine output, 24-h urinary sodium, Child Turcotte Pugh (CTP), model for end-stage liver disease (MELD) scores, survival at 6 months, incidence of acute kidney injury (AKI) and infections. RESULTS: The 2 groups were comparable at baseline. Control of ascites at 6 months was significantly better in group A than that in Group B (p = 0.04). Change in urinary sodium was significantly higher in Group A (p < 0.001]. However, there was no difference in change in urine output, CTP or MELD scores and survival (65% vs 72.2%, p = 0.75) between the groups at 6 months. Incidence of AKI (50% vs 15%, p = 0.04) and infections (55% vs 20%, p = 0.04) were significantly higher in Group A. CONCLUSION: Significantly better control of ascites and higher natriuresis are observed with dapagliflozin. However, it does not improve disease severity scores or survival, and is associated with increased AKI and infections (NCT05014594).

The role of urine sodium in acutely decompensated heart failure.

Background: Diuretic resistance is common and results in poor outcome. Spot urine sodium (UrNa) is suggested as a tool to tailor diuretics and improve efficacy of therapy. We prospectively evaluate the prevalence of diuretic resistance, predictors of low spot-UrNa and the prognostic value of spot-UrNa in an unselected ADHF population. Methods: Patients admitted for ADHF and treated with iv diuretics were included. Spot-UrNa was collected 2 h after administration of an IV diuretic bolus. The main endpoint was a composite of HF re-hospitalizations and all-cause mortality at 90 days follow-up. Results: 143 patients were included in this study (median age 81 [75 - 85] years, 55 % male), of which 50 % were newly diagnosed with HF. Low spot-UrNa was independently associated with worse renal function, low serum sodium, and systolic blood pressure, previous loop diuretic and SGLT2i use and loop diuretic administered dose. Both absolute spot-UrNa (HR 0.87, 95 % CI 0.79 - 0.95, P=0.003 per 10 mmol/L increase) and a urinary sodium ≥ 100 mmol/l (HR=0.51, 95 % CI 0.27 - 0.97, P=0.04) significantly predicted the composite endpoint. This association was no longer significant after correction for confounders. Patients with low spot-UrNa attained longer IV diuretic treatment and a higher cumulative IV diuretic dose. Conclusions: Spot-UrNa is prevalent and occurs more often in patients with more progressed cardio-renal disease. Spot-UrNa significantly predicts 90-day HF hospital-free survival in ADHF. Further studies are needed evaluating the effect of UrNa guided diuretic treatment on clinical endpoints.

Prevalence and characteristics of upfront diuretic resistance in acute heart failure: The P-Value-AHF study.

AIMS: Diuretic resistance (i.e., insufficient diuretic and natriuretic response to an appropriate dose of intravenously administered loop diuretic) is a major cause of insufficient decongestion in acute heart failure (AHF). Early assessment of diuretic and natriuretic response already after the first administration of loop diuretic is currently recommended, but few data exist on the prevalence and characteristics of upfront diuretic resistance in AHF. The aim of this sub-study of the P-Value-AHF randomized clinical trial was to investigate the prevalence and characteristics of upfront diuretic resistance in patients presenting with AHF in the emergency department (ED). METHODS: Consecutive patients presenting with a clinical diagnosis of AHF, ≥1 sign of congestion, and NT-proBNP >1000 ng/L between February and June 2024 were prospectively screened. Loop diuretics were administered per protocol: 40 mg furosemide i.v. in diuretic-naïve patients and those on oral torasemide <40 mg, 80 mg furosemide i.v. in patients on oral torasemide ≥40 mg daily. Urine output was measured over the following 2 h and in patients with urine volume <300 mL, urine sodium concentration was additionally measured in a spot sample. Upfront diuretic resistance was defined as urine volume <300 mL in 2 h and urine sodium concentration <70 mmol/L. RESULTS: From a total of 127 screened AHF patients presenting to the ED, 17 subjects were excluded after denial of informed consent and 17 could not be treated according to the protocol due to one or more exclusion criteria. Of the remaining 93 per-protocol-treated patients, 91 showed an adequate diuretic response either in terms of urine volume or urine sodium concentration. Only two of 93 patients (2.2%) met the criteria of upfront diuretic resistance. In a post-hoc analysis, patients with diuretic resistance had higher prevalence of chronic kidney or liver diseases, markedly lower blood pressure and heart rate, markedly higher serum creatinine and potassium levels, and lower serum sodium. Notably, clinical signs of congestion, circulating NT-proBNP, and left-ventricular ejection fraction were similar in both groups. CONCLUSIONS: Upfront diuretic resistance in an unselected population of AHF patients presenting to the ED affects only a minority of patients. These data highlight the importance of a standardized, protocolized approach to decongestive treatment in AHF, which includes the rapid administration of loop diuretics in an adequate dose. Pre-existing chronic kidney disease and high creatinine levels were more prevalent in patients with diuretic resistance.

Rationale and Design of the DECONGEST (Diuretic Treatment in Acute Heart Failure With Volume Overload Guided by Serial Spot Urine Sodium Assessment) Study.

AIMS: To evaluate whether early-combination diuretic therapy guided by serial post-diuretic urine sodium concentration (UNa+) assessments in acute heart failure (AHF) facilitates safe and effective decongestion. METHODS: The Diuretic Treatment in Acute Heart Failure with Volume Overload Guided by Serial Spot Urine Sodium Assessment (DECONGEST) study is a pragmatic, 2-center, randomized, parallel-arm, open-label study aiming to enroll 104 patients with AHF and clinically evident fluid overload requiring treatment with intravenous loop diuretics. Patients are randomized to receive standard of care or a bundled approach comprising: (1) systematic post-diuretic UNa+ assessments until successful decongestion, defined as no remaining clinical signs of fluid overload with a post-diuretic UNa+ ≤ 80 mmol/L; (2) thrice-daily intravenous loop diuretic bolus therapy, with dosing according to estimated glomerular filtration rate; (3) upfront use of intravenous acetazolamide (500 mg once daily [OD]); and (4) full nephron blockade with high-dose oral chlorthalidone (100 mg OD) and intravenous canreonate (200 mg OD) for diuretic resistance, defined as persisting signs of fluid overload with a post-diuretic UNa+ ≤ 80 mmol/L. The primary endpoint of the DECONGEST study is a hierarchical composite of (1) survival at 30 days; (2) days alive and out of hospital or care facility up to 30 days; and (3) greater relative decrease in natriuretic peptide levels from baseline to day 30. CONCLUSION: The DECONGEST study aims to determine whether an intensive diuretic regimen focused on early combination therapy, guided by serial post-diuretic UNa+ assessments, safely enhances decongestion, warranting further evaluation in a larger trial powered for clinical events.

GLP-1 receptor agonists may enhance the effects of desmopressin in individuals with AVP deficiency: a case series and proposed mechanism.

BACKGROUND: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have diverse effects on sodium and water homeostasis. They decrease thirst perception, potentially inhibit arginine vasopressin (AVP) production, and induce natriuresis. We present three cases of AVP deficiency (AVP-D) where GLP-1 RA initiation led to desmopressin dose reduction. CASES: Three patients with AVP-D on stable desmopressin therapy started GLP-1 RAs for type 2 diabetes mellitus or obesity. Following weight loss and decreased thirst, all patients reduced their desmopressin dose while maintaining normal thirst and urine output. DISCUSSION: GLP-1 RAs influence sodium and water homeostasis through various mechanisms. In individuals with intact AVP systems, GLP-1 RAs may directly suppress AVP production and induce natriuresis in the kidney leading to increased water excretion. In AVP-D, with exogenous desmopressin replacing endogenous AVP, the osmotic permeability of collecting ducts is primarily influenced by desmopressin dose. Thus, increased distal fluid delivery may allow for lower desmopressin doses to maintain water balance. CONCLUSION: Our findings indicate a potential interaction between GLP-1 RAs and desmopressin in AVP-D. Clinicians should reassess desmopressin dosage upon initiating GLP-1 RA therapy.

Renal Medulla in Hypertension.

Studies have found that blood flow to the renal medulla is an important determinant of pressure-natriuresis and the long-term regulation of arterial pressure. First, a brief review of methods developed enabling the study of the medullary circulation is presented. Second, studies performed in rats are presented showing medullary blood flow plays a vital role in the pressure-natriuresis relationship and thereby in hypertension. Third, it is shown that chronic reduction of medullary blood flow results in hypertension and that enhancement of medullary blood flow reduces hypertension hereditary models of both salt-sensitive rats and salt-resistant forms of hypertension. The key role that medullary nitric oxide production plays in protecting this region from ischemic injury associated with circulating vasoconstrictor agents and reactive oxygen species is presented. The studies cited are largely the work of my students, research fellows, and colleagues with whom I have performed these studies dating from the late 1980s to more recent years.

Nurse-led diuretic titration via a point-of-care urinary sodium sensor in patients with acute decompensated heart failure (EASY-HF): A single-centre, randomized, open-label study.

AIMS: Early evaluation of the natriuretic response is recommended to guide diuretic therapy in acute decompensated heart failure (ADHF). However, its implementation in daily practice is hampered by implementation barriers and increased time constraints. The Readily Available Urinary Sodium Analysis in Patients with Acute Decompensated Heart Failure (EASY-HF) study assessed the feasibility, efficacy and safety of a nurse-led urinary sodium-based diuretic titration protocol with the use of a point-of-care urinary sodium sensor. METHODS AND RESULTS: The EASY-HF study was a single-centre, randomized, open-label study comparing diuretic management at the treating physician's discretion as standard of care (SOC) with a nurse-led natriuresis-guided protocol in patients with ADHF. The LAQUAtwin Sodium Meter (HORIBA) was used as point-of-care sensor to measure urine sodium concentration. The primary endpoint was natriuresis after 48 h. Secondary endpoints included safety profile and user-friendliness of both the protocol and the point-of-care sensor. Sixty patients were randomized towards SOC (n = 30) versus protocolized care (n = 30). The mean age was 80 ± 8 years, 25% were women and median N-terminal pro-B-type natriuretic peptide was 4667 (2667-7709) ng/L. Natriuresis after 48 h was significantly higher in the protocolized versus SOC group (820 ± 279 vs. 657 ± 273 mmol; p = 0.027). Pre-defined safety endpoints were similar among both groups. The sensor-based protocol was evaluated as easy to use by the nursing staff, and preferred over urinary collections. CONCLUSION: A nurse-led diuretic titration protocol via a point-of-care urinary sodium sensor was feasible, safe and resulted in an increased natriuresis in ADHF compared to SOC.

Impact of natriuresis on worsening renal function during episodes of acute heart failure.

INTRODUCTION AND OBJECTIVES: Worsening renal function (WRF) is a frequent complication in acute heart failure (AHF) with a controversial prognostic value. We aimed to study the usefulness of natriuresis to evaluate WRF. METHODS: We conducted an observational, prospective, multicenter study of patients with AHF who underwent a furosemide stress test. The patients were classified according to whether WRF was present or absent and according to the median natriuretic response. The main endpoint was the combination of mortality, rehospitalization due to HF, and heart transplant at 6 months of follow-up. RESULTS: One hundred and fifty-six patients were enrolled, and WRF occurred in 60 (38.5%). The patients were divided into 4 groups: a) 47 (30.1%) no WRF/low UNa (UNa ≤ 109 mEq/L); b) 49 (31.4%) no WRF/high UNa (UNa >109 mEq/L); c) 31 (19.9%) WRF/low UNa and d) 29 (18.6%) WRF/high UNa. The parameters of the WRF/low UNa group showed higher clinical severity and worse diuretic and decongestive response. The development of WRF was associated with a higher risk of the combined event (HR, 1.88; 95%CI, 1.01-3.50; P=.046). When stratified by natriuretic response, WRF was associated with an increased risk of adverse events in patients with low natriuresis (HR, 2.28; 95%CI, 1.15-4.53; P=.019), but not in those with high natriuresis (HR, 1.18; 95%CI, 0.26-5.29; P=.826). CONCLUSIONS: Natriuresis could be a useful biomarker for interpreting and prognosticating WRF in AHF. WRF is associated with a higher risk of adverse events only in the context of low natriuresis.

The utility of urine sodium-guided diuresis during acute decompensated heart failure.

Diuresis to achieve decongestion is a central aim of therapy in patients hospitalized for acute decompensated heart failure (ADHF). While multiple approaches have been tried to achieve adequate decongestion rapidly while minimizing adverse effects, no single diuretic strategy has shown superiority, and there is a paucity of data and guidelines to utilize in making these decisions. Observational cohort studies have shown associations between urine sodium excretion and outcomes after hospitalization for ADHF. Urine chemistries (urine sodium ± urine creatinine) may guide diuretic titration during ADHF, and multiple randomized clinical trials have been designed to compare a strategy of urine chemistry-guided diuresis to usual care. This review will summarize current literature for diuretic monitoring and titration strategies, outline evidence gaps, and describe the recently completed and ongoing clinical trials to address these gaps in patients with ADHF with a particular focus on the utility of urine sodium-guided strategies.

State-of-the-Art-Review: Mechanisms of Action of SGLT2 Inhibitors and Clinical Implications.

BACKGROUND: Inhibitors of the Na+-coupled glucose transporter SGLT2 (SGLT2i) primarily shift the reabsorption of large amounts of glucose from the kidney's early proximal tubule to downstream tubular segments expressing SGLT1, and the non-reabsorbed glucose is spilled into the urine together with some osmotic diuresis. How can this protect the kidneys and heart from failing as observed in individuals with and without type 2 diabetes? GOAL: Mediation analyses identified clinical phenotypes of SGLT2i associated with improved kidney and heart outcome, including a reduction of plasma volume or increase in hematocrit, and lowering of serum urate levels and albuminuria. This review outlines how primary effects of SGLT2i on the early proximal tubule can explain these phenotypes. RESULTS: The physiology of tubule-glomerular communication provides the basis for acute lowering of GFR and glomerular capillary pressure, which contributes to lowering of albuminuria but also to long term preservation of GFR, at least in part by reducing kidney cortex oxygen demand. Functional co-regulation of SGLT2 with other sodium and metabolite transporters in the early proximal tubule explains why SGLT2i initially excrete more sodium than expected and are uricosuric, thereby reducing plasma volume and serum urate. Inhibition of SGLT2 reduces early proximal tubule gluco-toxicity and by shifting transport downstream may simulate "systemic hypoxia", and the resulting increase in erythropoiesis, together with the osmotic diuresis, enhances hematocrit and improves blood oxygen delivery. Cardio-renal protection by SGLT2i is also provided by a fasting-like and insulin-sparing metabolic phenotype and, potentially, by off-target effects on the heart and microbiotic formation of uremic toxins.

Acetazolamide therapy in patients with acute heart failure: a systematic review and meta-analysis of randomized controlled trials.

Acute heart failure (AHF) often leads to unfavorable outcomes due to fluid overload. While diuretics are the cornerstone treatment, acetazolamide may enhance diuretic efficiency by reducing sodium reabsorption. We performed a systematic review and meta-analysis on the effects of acetazolamide as an add-on therapy in patients with AHF compared to diuretic therapy. PubMed, Embase, and Cochrane databases were searched for randomized controlled trials (RCT). A random-effects model was employed to compute mean differences and risk ratios. Statistical analysis was performed using R software. The GRADE approach was used to rate the certainty of the evidence. We included 4 RCTs with 634 patients aged 68 to 81 years. Over a mean follow-up of 3 days to 34 months, acetazolamide significantly increased diuresis (MD 899.2 mL; 95% CI 249.5 to 1549; p < 0.01) and natriuresis (MD 72.44 mmol/L; 95% CI 39.4 to 105.4; p < 0.01) after 48 h of its administration. No association was found between acetazolamide use and WRF (RR 2.4; 95% CI 0.4 to 14.2; p = 0.3) or all-cause mortality (RR 1.2; 95% CI 0.8 to 1.9; p = 0.3). Clinical decongestion was significantly higher in the intervention group (RR 1.35; 95% CI 1.09 to 1.68; p = 0.01). Acetazolamide is an effective add-on therapy in patients with AHF, increasing diuresis, natriuresis, and clinical decongestion, but it was not associated with differences in mortality.

The endocrine basis of the cardio-renal axis: New perspectives regarding corin.

The central role of natriuretic peptides (NPs) in the complex cardio-renal integrated physiology and organ failure has been revealed over the last four decades. Atrial natriuretic peptide (ANP), the oldest representative of the NPs family, is produced through conversion of proANP to the mature peptide by corin, a trans-membrane protease localized to the cardiac myocyte membrane. Similarly, brain natriuretic peptide (BNP) is generated by furin, which cleaves proBNP to BNP in myocytes. Though the components of NPs system, their synthesis and target organs are well established, understanding their role in the interplay between the heart and the kidney is steadily evolving. In this context, Feldman et al. (New England Journal of Medicine, 389, 1685) recently described patients with hypertension, cardiomyopathy, atrial arrhythmia and left atrial fibrosis, associated with a homozygous loss-of-function variant of the gene encoding corin (Cor-/-). Notably, reduced baseline urinary electrolyte and creatinine excretion have been observed in one of the studied patients. This renal excretory functional impairment could be attributed to the lack of cardiac-derived ANP in these patients, as implied by Feldman et al. Yet, in this mini-review we suggest that this aberrant renal manifestation may principally stem from lack of local ANP production at renal tissue, as corin is normally expressed in proximal tubules, Henle's loop and collecting ducts, with locally produced ANP provoking Na+ and water exertion. Collectively, it seems that beside the classic well-established cardio-renal axis, the renal NPs system functions as local endocrine machinery in the regulation of sodium excretion.

Renal function in PUSH-AHF: a summary of newly released data from the 2024 Annual Congress of the Heart Failure Association of the ESC.

The Pragmatic Urinary Sodium-based algoritHm in Acute Heart Failure (PUSH-AHF) study, published in August of 2023, was the first randomized clinical trial to compare natriuresis-guided decongestion (based on spot urinary sodium measurement) to standard of care in patients with acute heart failure with congestion receiving loop diuretic therapy. Based on results from their trial, the authors concluded that natriuresis-guided loop diuretic treatment was safe and improved natriuresis and diuresis without impacting long-term clinical outcomes. The original PUSH-AHF trial included limited information about renal outcomes and left clinicians with important questions about how natriuresis-guided decongestion might affect their patients' renal function. On May 12, 2024, however, at the 2024 Annual Congress of the HFA-ESC, Dr. Kevin Damman provided an in-depth exploration of renal outcomes from the trial when he presented a pre-specified, secondary analysis, renal function in the PUSH-AHF trial. This review puts the sub-study findings into context by considering the history of the original trial from which they came from and explaining the need for a close study of its renal outcomes particularly. It highlights the potential impact of renal function in PUSH-AHF on clinical practice and future directions that should be considered by the cardiology research community.

Augmentation of Nitric Oxide Deficient Hypertension by High Salt Diet Is Associated With Reduced TNF-α Receptor Type 1 Expression in the Kidneys.

BACKGROUND: High salt (HS) intake induces an augmented hypertensive response to nitric oxide (NO) inhibition, though it causes minimal changes in blood pressure (BP) in NO intact condition. The cause of such augmentation is not known. HS induces tumor necrosis factor-alpha (TNFα) production that causes natriuresis via activation of its receptor type 1 (TNFR1). We hypothesized that NO deficiency reduces renal TNFR1 activity, leading to enhanced sodium retention and hypertension. METHODS: We examined the changes in renal TNFR1 protein expression (Immunohistochemistry analyses) after HS (4% NaCl) intake in wild-type mice (WT, C57BL6) treated with a NO synthase (NOS) inhibitor, nitro-l-arginine methyl ester (L-NAME; 0.05 mg/min/g; osmotic mini-pump), as well as in endothelial NOS knockout mice (eNOSKO) and compared the responses in WT mice with normal salt (NS; 0.3% NaCl) intake. BP was measured with tail-cuff plethysmography and 24-hour urine collections were made using metabolic cages. RESULTS: HS alone did not alter mean BP in untreated mice (76 ±â€…3 to 77 ±â€…1 mm Hg) but induced an augmented response in L-NAME treated (106 ±â€…1 vs. 97 ±â€…2 mm Hg) and in eNOSKO (107 ±â€…2 vs. 89 ±â€…3 mm Hg) mice. The percentage area of TNFR1 expression in renal tissue was higher in WT + HS (4.1 + 0.5%) than in WT + NS mice (2.7 ±â€…0.6%). However, TNFR1 expression was significantly lower in L-NAME treated WT + NS (0.9 ±â€…0.1%) and in eNOSKO + NS (1.4 ±â€…0.2%) than in both WT + NS and WT + HS mice. CONCLUSIONS: These data indicate that TNFR1 activity is downregulated in NO deficient conditions, which facilitates salt retention leading to augmented hypertension during HS intake.

Inhibition of mTORC2 promotes natriuresis in Dahl salt-sensitive rats via the decrease of NCC and ENaC activity.

We have previously observed that prolonged administration of rapamycin, an inhibitor targeting the mammalian target of rapamycin complex (mTORC)1, partially reduced hypertension and alleviated kidney inflammation in Dahl salt-sensitive (SS) rats. In contrast, treatment with PP242, an inhibitor affecting both mTORC1/mTORC2, not only completely prevented hypertension but also provided substantial protection against kidney injury. Notably, PP242 exhibited potent natriuretic effects that were not evident with rapamycin. The primary objective of this study was to pinpoint the specific tubular sites responsible for the natriuretic effect of PP242 in SS rats subjected to either 0.4% NaCl (normal salt) or 4.0% NaCl (high salt) diet. Acute effects of PP242 on natriuretic, diuretic, and kaliuretic responses were determined in unanesthetized SS rats utilizing benzamil, furosemide, or hydrochlorothiazide [inhibitors of epithelial Na+ channel (ENaC), Na-K-2Cl cotransporter (NKCC2), or Na-Cl cotransporter (NCC), respectively] either administered alone or in combination. The findings indicate that the natriuretic effects of PP242 in SS rats stem predominantly from the inhibition of NCC and a reduction of ENaC open probability. Molecular analysis revealed that mTORC2 regulates NCC activity through protein phosphorylation and ENaC activity through proteolytic cleavage in vivo. Evidence also indicated that PP242 also prevents the loss of K+ associated with the inhibition of NCC. These findings suggest that PP242 may represent an improved therapeutic approach for antihypertensive intervention, potentially controlling blood pressure and mitigating kidney injury in salt-sensitive human subjects.NEW & NOTEWORTHY This study explored mechanisms underlying the natriuretic effects of mammalian target of rapamycin protein complex 2 inhibition using PP242 and revealed both epithelial Na+ channel and Na-Cl cotransporter in the distal tubular segments were potentially inhibited. These observations, with prior lab evidence, indicate that PP242 prevents hypertension via its potent inhibitory effects on these specific sodium transporters and by reducing renal immune responses. This dual action, coupled with potassium sparing effects, suggests an improved approach for managing hypertension and associated kidney damage.

Basal natriuresis as a predictor of diuretic resistance and clinical evolution in acute heart failure.

BACKGROUND: Some clinical guidelines recommend serial measurement of natriuresis to detect diuretic resistance (DR) in acute heart failure (AHF) patients, but it adds complexity to the management. OBJECTIVES: To correlate a single measurement of basal natriuresis (BN) on admission with the development of DR and clinical evolution in AHF hospitalized patients. METHODS: Prospective and multicenter study included AHF hospitalized patients, without shock or creatinine >2.5mg%. Patients received 40mg of intravenous furosemide on admission, then BN was measured, and diuretic treatment was guided by protocol. BN was considered low if <70 meq/L. DR was defined as the need of furosemide >240mg/day, tubular blockade (TB), hypertonic saline solution (HSS) or renal replacement therapy (RRT). In-hospital cardiovascular (CV) mortality, CV mortality and AHF readmissions at 60-day post-discharge were evaluated. RESULTS: 157 patients were included. BN was low in 22%. DR was development in 19% (12.7% furosemide >240mg/day, 8% TB, 4% RRT). Low NB was associated with DR (44% vs 12%; p 0.0001), persistence of congestion (26.5% vs 11.4%; p 0.05), furosemide >240 mg/day (29% vs 8%; p 0.003), higher cumulative furosemide dose at 72 hours (220 vs 160mg; p 0.0001), TB (20.6 vs 4.9%; p 0.008), RRT (11.8 vs 1.6%; p 0.02), worsening of AHF (27% vs 9%; p 0.01), inotropes use (21% vs 7%; p 0.48), respiratory assistance (12% vs 2%; p 0.02) and a higher in-hospital CV mortality (12% vs 4%; p 0.1). No association was demonstrated with post-discharge endpoints. CONCLUSIONS: In AHF patients, low BN was associated with DR, persistent congestion, need for aggressive decongestion strategies, and worse in-hospital evolution.

Osmolality in oral supplements drives ileostomy output: Defining the Goldilocks zone.

BACKGROUND: Patients with an ileostomy often have impaired quality of life, sodium depletion, secondary hyperaldosteronism, and other organ-specific pathologies. The osmolality of oral supplements influences ileostomy output and increases sodium loss. We hypothesized the existence of an osmolality range in which fluid absorption and secondary natriuresis are optimal. METHODS: This was a single-center, quasi-randomized crossover intervention study, including patients with an ileostomy and no home parenteral support. After an 8-h fasting period, each patient ingested 500 mL of 3-18 different oral supplements and a standardized meal during the various intervention periods, followed by a 6-h collection of ileostomy and urine outputs. The primary outcome was 6-h ileostomy output. RESULTS: A total of 14 ileostomy patients with a median age of 65 years (interquartile range 38-70 years) were included. The association between osmolalities (range 5-1352 mOsm/kg) and ileostomy output forecasted an S-curve. A linear association between osmolality of oral supplements (range 290-600 mOsm/kg) and ileostomy output was identified and assessed with a mixed-effects model. Ileostomy output increased by 57 g/6 h (95% confidence interval (CI) 21-94) when the oral supplement osmolality increased by 100 mOsm/kg (p = 0.005). CONCLUSION: Osmolality in oral supplements correlated with ileostomy output. Our results indicate that patients with an ileostomy may benefit from increased ingestion of oral supplements with osmolalities between 100 and 290 mOsm/kg. We define this range as the Goldilocks zone, equivalent to optimal fluid and electrolyte absorption.