A novel SGLT-2 score to identify HFpEF patients who may benefit from SGLT-2 inhibitors

Background

Established heart failure (HF) treatments have shown no effects in HF and preserved ejection fraction (HFpEF). Subgroup analyses of the HFpEF populations suggest that certain patients benefit from HF treatments. This underlines the importance of individualized therapy regimens in HFpEF. Sodium-glucose transporter 2 (SGLT-2) inhibitors are emerging as a promising treatment of HF. The mechanisms leading to improved outcomes include 1) treatment of diabetes, 2) osmodiuresis preventing volume overload, 3) enhancement of the cardio protective Angiotensin (Ang) 1–7 pathway, instead of Ang II. We aimed to characterize patients by factors which are modified by SGLT-2 inhibitors to identify individuals who may benefit from these drugs.

Methods

HFpEF patients were included in a single center registry. Baseline evaluation included assessment of HbA1c, fluid status measured by body composition monitor and plasma angiotensin concentration. A “SGLT-2 score” with a maximum of 3 points was calculated using the following parameters: 1) HbA1c >6.5%, 2) overhydration, defined as a fluid overload of >1,5L and 3) plasma renin activity (PRA) levels above the median as a parameter of over-all RAS activity. Primary outcome was defined as all-cause death or HF hospitalization. All parameters used in the “SGLT-2 score” were independently predictive for the chosen endpoint. Kaplan Meier analyses was used to show the association between the score and outcomes.

Results

90 patients were included in this registry. Median HbA1c was 6.0%, median fluid status was 1.2L and the median Ang II levels in the “high PRA-group” were 5.35.1 pmol/L. After a mean follow up time of 44.0±38.7 months, 60 patients (66.6%) reached the endpoint. Kaplan Meier analysis showed an association between SGLT-2 score and outcome (p=0.003).

Conclusion

Patients with HbA1c >6.5%, overhydration and high RAS activity have poor outcomes. We propose the future use of this score to identify a subgroup of HFpEF patients who may benefit from SGLT-2 inhibitors.

Kaplan Meier analysis

Funding Acknowledgement

Type of funding source: None

Role of angiotensin peptides in risk stratification and prognostication for heart failure: focus on plasma Ang 1–7/Ang II ratio

Background

ACE2 and Ang 1–7 are endogenous negative regulators of the renin-angiotensin system (RAS) exerting cardioprotective effects in models of heart failure (HF). Recombinant ACE2 markedly increased plasma Ang 1–7 and lowered Ang II levels in clinical trials. Elevated plasma ACE2 activity is associated with adverse outcomes in HF patients. However, the direct effects of systemic and tissue ACE2 activation on angiotensin peptides in relation to long-term HF outcomes has yet to be examined.

Purpose

To generate insights into the ACE2 mediated cardioprotective arm through the relative levels of its substrates and products using the plasma Ang 1–7/Ang II ratio, and assess its prognostic utility in HF patients.

Methods

110 HF patients were prospectively enrolled from outpatient clinics and the emergency department. Comprehensive circulating and equilibrium levels of plasma angiotensin peptides were assessed using novel liquid chromatography-mass spectrometry/mass spectroscopy techniques. Plasma aldosterone, BNP, active renin activity and clinical profiles were captured at baseline. Patients were stratified into above and below median cohorts based on equilibrium and circulating levels of Ang 1–7/Ang II ratio, as a surrogate for ACE2 functionality. During a median follow-up of 5.1±0.8 years, composite clinical outcomes were assessed through all-cause in-patient hospitalizations and mortality.

Results

Circulating and equilibrium angiotensin peptide levels strongly correlated in our patient cohort. All-cause mortality for HF patients with equilibrium Ang 1–7/Ang II ratios above the median showed higher survival rates compared to below median patients (76.4% vs. 50.9%; p=0.004); similar results were observed for circulating Ang 1–7/Ang II ratios (72.7% vs. 54.5%; p=0.041). Adjusting for covariates, elevated equilibrium (HR: 0.24; 95% CI: 0.09 to 0.69; p=0.008) and circulating (HR: 0.35; 95% CI: 0.13 to 0.94; p=0.036) Ang 1–7/Ang II ratios was associated with improved survival. Lower hospitalization duration was also associated with elevated equilibrium (p<0.001) and circulating (p=0.023) Ang 1–7/Ang II ratios. In nested models, net reclassification analysis showed considerable improvement in risk prediction for all-cause mortality at 5 years provided by both the equilibrium (+45.0% [95% CI: 7.3% to 82.7%]) and circulating Ang 1–7/Ang II ratios (+24.3% [95% CI: 0.4% to 59.6%]) respectively.

Conclusions

We extensively profiled plasma angiotensin peptides in HF patients and identified elevated ACE2 signature, reflected through the Ang 1–7/Ang II ratio, as an independent and incremental predictor of beneficial outcomes, higher survival rate, and decreased hospitalization duration. These findings provide important clinical evidence supporting strategies aiming to promote the beneficial ACE2/Ang 1–7/Mas receptor axis concurrent with RAS blockade therapies inhibiting the detrimental ACE/Ang II/AT1 receptor axis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Alberta Innovates, Canadian Institute of Health Research

Comparison between the effects of torsemide and furosemide on the renin-angiotensin-aldosterone system of normal dogs

INTRODUCTION/OBJECTIVES

We hypothesized that torsemide and furosemide, at approximately equipotent dosages (similar diuresis), would have comparable effects on the circulating renin-angiotensin-aldosterone system.

ANIMALS, MATERIALS AND METHODS

Six, healthy, middle-aged, male Beagles were randomized to receive torsemide (0.1 mg/kg PO q 12 h), furosemide (2.0 mg/kg PO q 12 h), or placebo for 10 days during three separate periods, separated by a 10-day washout period, in a crossover design. Blood was collected on days 1, 5, and 9 and 24-h urine collection ended on days 2, 6, and 10. After repeated measures analysis and Bonferonni correction, variables with an adjusted p<0.05 were investigated further, using Tukey's method.

RESULTS

Twenty-four-hour urine production differed significantly between the diuretics only on day 10, with torsemide causing a 38% greater diuresis than furosemide. There was, however, no significant difference in average 3-day diuresis. There were no significant differences between diuretics in the 24-h urinary excretion of sodium, chloride, or potassium, though furosemide caused less kaliuresis than torsemide. Serum renin, angiotensin II, and aldosterone and the urine aldosterone-to-creatinine ratio were significantly increased in the diuretic groups, as compared to placebo on days 5/6 and 9/10. There were no significant differences in these values between diuretics. Creatinine and blood urea nitrogen concentrations rose comparably in the diuretic groups, remaining within reference intervals in all dogs.

CONCLUSIONS

At approximately equipotent dosages (20:1), torsemide and furosemide produced comparable renin-angiotensin-aldosterone system activation. Torsemide's similar potassium excretion profile to furosemide decreases support for a hypothesized mineralocorticoid-receptor blocking capability.

P5448Enzymatic regulation of the myocardial tissue renin-angiotensin-system of the failing heart

Background

In heart failure with reduced ejection fraction (HFrEF) the renin-angiotensin-system (RAS) is dysregulated and serves as therapeutic target. Research has been focusing on plasma RAS. Information on tissue RAS is scarce although assumedly more crucial for myocardial function. Among known angiotensins, only AngII and AngIII are detectable in the failing heart. Plasma samples in HFrEF show high AngI and AngII levels with clearly distinguishable AngI/AngII ratios for different RAS-inhibitors. AngII and AngIII levels in the myocardium were comparable for different RAS-inhibitors, i.e. no RAS-blocker, ACE-inhibitor, ARB or angiotensin-receptor neprilysin-inhibitor (ARNI). Here we aimed to elucidate the metabolic regulation of tissue RAS enzymes for these four different modalities of RAS-inhibition.

Methods

Enzyme regulation and metabolic activities were investigated in myocardial samples of end-stage HFrEF patients undergoing heart transplantation with a mass-spectrometry based method. Concentrations of respective angiotensin metabolites AngI, AngII, Ang1–7, AngIII, Ang1–5 and AngIV (RAS-fingerprints) were investigated after adding AngI or AngII and incubation to display metabolic patterns of the main plasma angiotensins. Metabolic activities of distinct enzymes have been assessed for the no therapy and ACE-I subgroups. Patients were stratified according to background therapy with RAS-inhibitors.

Results

A total of 30 patients were included (n=6 without RAS-blockade, n=16 with ACE-I, n=6 with ARB, n=2 with ARNI). Median age was 55 (IQR 45–63) years, 87%were male. Etiology of HF was ischemic in 40%, median NT-proBNP levels were 3498pg/ml (IQR 1761–8400). Patterns for tissue RAS metabolism of AngI and AngII was visually similar for all groups, indicating comparable regulation of tissue RAS enzymes independent from therapy (Figure 1). The formation of AngII from AngI was mainly chymase dependent with conversion rates of 99.4 (IQR 77.0–254.1) (pg/μg protein)/h for ACE-I and 141.8 (IQR 67.9–369.2) (pg/μg protein)/h for no RAS-blockade, whereas ACE-related generation of AngII was under the detection limit. The formation of Ang1–7 from AngI was mediated by NEP and PEP. The contribution of NEP was significantly higher [5022 (IQR 5002–5286) (pg/μg)/h vs 3555 (IQR 3351–3849) (pg/μg)/h, p=0.005 for the ACE-I group and 4729 (IQR 4438–6135) (pg/μg)/h vs 3601 (IQR 3052–4182) (pg/μg)/h, p=0.012 for no RAS-blockade]. No differences in tissue enzymatic activities between ACE-I and no therapy, as already indicated by the metabolization patterns occurred.

Figure 1

Conclusions

Enzymatic tissue RAS regulation in end-stage HF seems to be independent from the mode of established RAS-inhibitor therapy.In contrast to plasma, AngII formation of the tissue is mainly chymase dependent, whereas ACE seems to play an unsignificant role. NEP has a substantial role in generating beneficial Ang1–7 from AngI. The impact of NEP inhibition by ARNI on tissue RAS and mechanism of action have to be further investigated.

P1661The myocardial tissue Renin-Angiotensin-System (RAS) of the failing heart

Background

Prognosis of patients with HFrEF remains poor despite recent advances in pharmacologic therapy as the introduction of the angiotensin-receptor neprilysin-inhibitor (ARNI). The Renin-Angiotensin-System (RAS) is dysregulated in HF with elevated AngII levels as a central driver of disease progression. The myocardium is capable of synthesizing all RAS components resulting in tissue specific angiotensin levels. Neprilysin (NEP) catalyzes the generation of Ang1–7 which counteracts the deleterious effects of AngII. Myocardial tissue angiotensins of the failing heart and the role of long-lasting RAS-inhibitor therapy and particularly NEP inhibition on tissue RAS have not been investigated yet.

Methods

Concentrations of AngI, AngII, Ang1–7, AngIII, Ang1–5 and AngIV (RAS-fingerprints) were investigated in myocardial samples of end-stage HFrEF patients undergoing heart transplantation with a mass-spectrometry based method. Patients were stratified according to background therapy with RAS-inhibitors and variables were compared by a non-parametrical test.

Results

A total of 30 patients were included (n=6 without RAS-blockade, n=16 with ACE-I, n=6 with ARB and n=2 with ARNI). Median age was 55 (IQR 45–63) years and 87% of patients were male. 40% of patients had an ischemic etiology of HF, median NT-proBNP levels were 3498pg/ml (IQR 1761–8400). Tissue RAS patterns were visually similar between all groups (Figure 1). Myocardial AngI, Ang1–7, Ang1–5 and AngIV levels were below the detection limit for all samples. Median tissue AngII and AngIII concentrations across all samples were 83.1pg/ml (IQR 29.3–196.6) and 26.4pg/ml (IQR 5.0–64.5). Despite different background RAS-inhibitor therapy, AngII and AngIII levels were comparable between all groups [median (IQR) in pg/ml – AngII: 51.5 (41.5–123.8) vs. 72.4 (28.5–177.6) vs. 176.1 (22.4–286.8) vs. 266.0 (108.2–423.8); p=ns and 26.4 (5.0–89.2) vs. 23.2 (5.0–59.3) vs. 39.4 (5.0–94.3) vs. 105.9 (46.5–165.3); p=ns for no therapy, ACE-I, ARB and ARNI respectively].

Figure 1. RAS-fingerprints of the failing heart according to RAS-inhibiton. Numbers in brackets indicate the specific angiotensin peptides. Side of spheres and numbers beside represent absolute concentrations of angiotensins (pg/ml, median value).

Conclusions

Although in the plasma of HFrEF patients only AngI and AngII are detectable at substantial concentrations, the predominant angiotensins of the failing heart are AngII and AngIII. AngII levels are high in the failing heart supporting the hypothesis that excess AngII is involved in disease progression. AngIII similarly increases cardiac sympathetic activity assumedly potentiating further deteoriation. The modality of long established RAS-inhibitor therapy in end-stage HF, particularly the inhibition of NEP, seems to have no (more) influence on myocardial tissue RAS regulation. The impact of NEP inhibition by ARNI on tissue RAS enzymes and mechanism of action need to be further investigated.

Quantification of systemic renin-angiotensin system peptides of hypertensive black and white African men established from the RAS-Fingerprint®

Objective:

The objective of this study was to make use of a quantitative and qualitative approach comparing the systemic renin-angiotensin system (RAS) of hypertensive black and white African men by using RAS equilibrium analysis.

Materials and methods:

This sub-study involved 23 black (n = 15) and white (n = 8) hypertensive men aged 39.5–41 years, living in the North West Province of South Africa. The RAS-Fingerprinting was determined with LC-MS/MS quantification of angiotensin peptides. Blood pressure and other variables were determined with known methods.

Results:

The main finding of this study was the significant lower Ang I (<5.0 and 45.1 pg/ml; p = 0.005) and Ang II (15.6 and 123.9 pg/ml; p ⩽ 0.001) encountered in the hypertensive black African men compared to their white counterparts. Levels of Ang 1-5 (downstream metabolite of Ang 1-7) (1.8 and 3.0 pg/ml), were detected in black and white hypertensive men, respectively.

Conclusions:

The observed differences between circulating RAS components, which are reflected via equilibrium angiotensin levels, point to a distinctive molecular regulation of the RAAS in the two study cohorts. The increased peripheral resistance observed in hypertensive black individuals might take over a dominant role in control of blood pressure in this study population. A novel highly sensitive LC-MS/MS method resolved the issue of peptide recovery variations during sample preparation by using internal standards for each individual angiotensin metabolite.

Weight loss and weight regain-5-year follow-up for circular- vs. linear-stapled gastrojejunostomy in laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Weight regain (WR) occurs in some patients after laparoscopic Roux-en-Y gastric bypass (LRYGBP). Loss of restriction due to dilation of the gastrojejunostomy (GJS) or the gastric pouch might be the main cause for WR. With different techniques available for the establishment of the GJS, the surgical technique might influence long-term success.

METHODS

We present a 5-year follow-up for weight loss and WR of a matched-pair study comparing circular stapled (CSA) to linear stapled (LSA) GJS in a series of 150 patients who underwent primary antecolic antegastric LRYGBP. Complete 5-year follow-up was obtained for 79 % of the patients.

RESULTS

Excess BMI loss (EBL) at 3 months was better with the CSA (p = 0.02) and comparable thereafter. The 5-year %EBL was 67.3 ± 23.2 vs. 73.3 ± 24.3 % (CSA vs. LSA, p = 0.19) WR of > 10 kg from nadir was found in 24 patients (16 %) with higher incidence in CSA than in LSA patients (20 % vs. 12 %). The %WR was comparable for both groups, 16 ± 13 vs. 15 ± 19 % (CSA vs. LSA, p = 0.345). Eleven patients underwent surgical re-intervention for WR by placement of a non-adjustable band (n = 2), adjustable band (n = 7) and conversion to distal gastric bypass (n = 2).

CONCLUSIONS

CSA and LSA lead to comparable weight loss in this 5-year follow-up. More patients in the CSA group had WR. Weight regain of more than 10 kg was found in one out of seven patients within 5 years postoperatively.

CMV late phase-induced mTOR activation is essential for efficient virus replication in polarized human macrophages

Human cytomegalovirus (CMV) remains one of the most important pathogens following solid-organ transplantation. Mounting evidence indicates that mammalian target of rapamycin (mTOR) inhibitors may decrease the incidence of CMV infection in solid-organ recipients. Here we aimed at elucidating the molecular mechanisms of this effect by employing a human CMV (HCMV) infection model in human macrophages, since myeloid cells are the principal in vivo targets of HCMV. We demonstrate a highly divergent host cell permissiveness for HCMV with optimal infection susceptibility in M2 but not M1 polarized macrophages. Employing an ultrahigh purified HCMV stock we observed rapamycin-independent viral entry and induction of IFN-β transcripts, but no proinflammatory cytokines or mitogen-activated protein kinases and mTOR activation early after infection. However, in the late infection phase, sustained mTOR activation was observed in HCMV-infected cells and was required for efficient viral protein synthesis including the viral late phase proteins pUL-44 and pp65. Accordingly, rapamycin strongly suppressed CMV replication 3 and 5 days postinfection in macrophages. In conclusion, these data indicate that mTOR is essential for virus replication during late phases of the viral cycle in myeloid cells and might explain the potent anti-CMV effects of mTOR inhibitors after organ transplantation.

The Novel Immunosuppressant FK778 Inhibits Formation of the Immunologic Synapse

The malononitrilamide FK778 is a derivative of A77 1726, the active metabolite of the antirheumatic drug leflunomide. A77 1726 inhibits de novo pyrimidine synthesis and activity of Src-family kinases; thus, it may interfere with T-cell proliferation as well as with early T-cell signaling. Formation of a stable interaction between T cells and antigen-presenting cells (APC)--the immunologic synapse--has emerged to be of crucial importance for T-cell activation. Here in we show that FK778 inhibits formation of the immunologic synapse by blocking superantigen-stimulated relocalization of adhesion (LFA-1), and signaling molecules (CD3) to the T-cell/APC contact site. These data show that FK778 affects T-cell/APC interactions, particularly events crucial for T-cell adhesion and formation of stable conjugates underlying sustained and effective T-cell activation. Thus, in this model system close to physiologic T-cell stimulation, FK778 affects critical events in the course of T-cell-mediated immune responses earlier than T-cell proliferation, which may contribute to its immunosuppressive potential.